Optical parametric oscillation in microcavities based on ... - IEEE Xplore

IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 39, NO. 4, APRIL 2003

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Optical Parametric Oscillation in Microcavities Based on Isotropic Semiconductors: A Theoretical Study Riad Haïdar, Nicolas Forget, and Emmanuel Rosencher, Senior Member, IEEE

Abstract—We present what we believe to be the first theoretical study of optical parametric oscillations in isotropic semiconductor microcavities. We have made use of the well-known possibilities of Bragg mirrors with very high reflectivities. The parametric oscillation conditions are derived in a very general and comprehensive way. Design rules are thus defined for optimum nonlinear microcavities. This theory is applied to GaAs materials (a semiconductor of the optoelectronic main stream) in which it is shown that threshold conditions far below optical damage may be obtained for reasonable values of the mirror reflectivities. Index Terms—Integrated optics, nonlinear optics, semiconductor materials.

I. INTRODUCTION

F

OR MORE than 30 years, important efforts have been devoted to the study of nonlinear optical properties of optoelectronic-grade semiconducting materials in view of the realization of optical parametric oscillators in the mid-infrared [1], [2]. Mid-infrared tunable sources are indeed of considerable interest for applications such as environment monitoring, chemical engineering, …. Optical parametric generation is indeed a good candidate for the production of mid-infrared wavelengths pumped by common near-infrared sources (Nd:YAG, …). However, apart from a few peculiar chalcopyrite materials (ZnGeP , AgGaSe , …), most of the usual nonlinear crystals absorb strongly above 5 m. On the other hand, semiconductors of the main technological stream (GaAs, InP, and to a less extent GaP, ZnSe,…) are excellent candidates for optical frequency conversion because of: 1) their high nonlinear suscep; 2) their high threshold damage power; 3) their extibility cellent transparency over the 1–15- m range; 4) their good mechanical properties; and 5) the possibility of future integration with the pumping source [3]. However, most of these materials are isotropic so that no birefringence phase-matching scenarios are available. Recently, several new phase-matching techniques have been investigated: artificial birefringence in GaAs–AlOx waveguides [4], quasiphase matching by alternate stacks [5] or localized epitaxy [6], …. An alternative way has also been proposed which consists in enhancing parametric interactions using a GaAs microcavity. In such a structure, the nonlinear material (e.g., GaAs) is clad between two highly reflecting Bragg mirrors (e.g., GaAs–AlGaAs) [7]. For second harmonic generation (SHG), the thickManuscript received March 1, 2002; revised October 30, 2002. This work was supported by the European Community under the MOPOSC project. The authors are with the Departement de Mesures Physiques, Office National d’Etudes et de Recherches Aerospatiales (ONERA), 91761 Palaiseau Cedex, France. Digital Object Identifier 10.1109/JQE.2003.809331

ness of the nonlinear medium is chosen close to ( is the fundamental wavelength) so that Fabry–Perot resonance effects greatly enhance parametric conversion. Such a structure has been realized by molecular beam epitaxy and the proposition has been experimentally verified [8]. However, the overall conversion yield is somewhat disappointing, mainly because the thickness of the nonlinear active material is very small, i.e., typically in the 0.5- m range. In this paper, we propose a new avenue to realize optical parametric oscillators in isotropic semiconductor cavities. The main ingredients for potential success are the following. • Parametric interaction is realized in the mid-infrared: this has the following four advantages. First, the phase-miscan be very match (or misnamed coherence) lengths large. This is due to the smaller optical dispersion when the photon energies are far smaller than the semiconductor energy gap. Indeed the phase-mismatch lengths have recently been measured in GaAs and ZnSe wedges and found to be, respectively, in the 40- and 80- m range when pumped in the 2- m range [9]. The GaAs cavity thickness is then chosen equal to the phase-mismatch length; an appreciable amount of parametric conversion can then be obtained in one single pass. Incidentally, in order to deal with handy GaAs wafers, a thickness of 7 or 9 phase-mismatch length may be used, i.e., in the 250 to 350 m range. Second, two-photon absorption (which limits the pumping power in the 1- m range) will be avoided. Third, the quantum defect is smaller than if pumped by the usual near 1- m source. The fourth point is that, for future applications, excellent 2- m sources may now be found, either semiconducting ones or fiber ones. • Use of epitaxial GaAs–AlGaAs Bragg reflectors: these dielectric mirrors may have extremely high reflectivities ( 99.5%) and very sophisticated phase behavior thanks to the knowledge developed for VCSELs and microcavities. High reflectivities should help to match oscillating conditions within the semiconductor damage threshold limit, as will be shown. Let us note that additional advantages are involved in this structure due to the small thickness of the Bragg cavity. • The photon lifetime is very small so that even with short pumping pulses (1 to 10 ns) the structure behaves in a cw way. This minimizes the OPO threshold [10]. • The focusing can be very high without degrading the parametric gain which will also help in obtaining parametric oscillation threshold (for instance, with a waist of 50 m, the Rayleigh zone is 8-mm long which, compared to the cavity thickness of 0.3 mm, should ensure a good optical coupling in the microcavity).

0018-9197/03$17.00 © 2003 IEEE

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The purpose of this paper is, thus, to theoretically analyze the conditions for optical parametric oscillations in a semiconductor cavity. In Section II, we present the nonlinear propagation equations in the microcavity which allow us to derive the parametric oscillation conditions. In Section III, these conditions are exploited to investigate GaAs–AlGaAs structure potentialities for OPO operations without pump reflection. In Section IV, the cavity design for minimum threshold conditions are presented. In Section V, the modal behavior of nonlinear microcavities is analyzed. Eventually, the conclusions are drawn in Section VI. Unavoidable pump reflection is briefly analyzed in the Appendix. II. NONLINEAR PROPAGATION EQUATIONS A major difference of this approach compared to the one of [7] is that the semiconductor cavity thickness is assumed to be large compared to the different interacting wavelengths. The interacting waves are thus assumed to be slowly varying, meaning that they may be written as:

Fig. 1. Scheme of the various waves interacting parametrically in the nonlinear cavity: p stands for pump, i for idler, s for signal, l for left, and r for right.

in which the interaction equations may be written as (4)

(1) with the envelope approximation

which is indeed invariant by translation. The change of coordinates is given by In this equation, is the wavenumber, is the wave pulsation, means that the wave is propagating to the right (see Fig. 1), and takes the values of (pump), (signal), is the envelope function and is the and (idler). propagating wave field. ( desIntroducing the amplitude ignate the optical indices of the different waves) and its prop, assuming no agating wave counterpart and taking the pump depletion i.e., , the parametric interaction between phase reference the amplitudes can be written as [11]

with (5) The solution of coupled (4) may then be easily found (6) where

is the parametric interaction matrix (7a)

(2)

with its elements given by

In (2)

is the nonlinear coupling coefficient where is the light velocity, is the input pump power, is the vacuum impedance are the wavelengths and is the (377 ), ). phase-mismatch wavevector ( It is very important to note that (2) is not invariant by translation. This leads to extreme difficulties in algebra when dealing with boundary conditions or counter-propagating waves. In order to solve this problem, we thus introduce the rotating phase coordinates (3)

(7b) At this stage, one has to note that the peculiarity of these isotropic materials cavities is that the phase-mismatch m m generation wavevector (typically 10 cm for in GaAs) is far higher than the attainable parametric gain (typically a few cm ), i.e., is a real number

(7c)

HAÏDAR et al.: OPTICAL PARAMETRIC OSCILLATION IN MICROCAVITIES BASED ON ISOTROPIC SEMICONDUCTORS

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Now, similar equations may be written for the counter-propagation waves (in the left direction)

Now the optical parametric oscillation is obtained once the cavity can sustain a stationary round trip of the waves, i.e.,

(8) The parametric equations are similar to (4), provided that we and . The make the following changes solution of the nonlinear parametric interaction in the cavity is now given by

(15)

(9)

This is possible for a nonvanishing field only if the following condition is fulfilled: (16) Equation (16) is the main result of this paper. We will now investigate the application of this equation to different experimental conditions.

in which the parametric interaction matrix is III. OPO THRESHOLD WITH NO PUMP REFLECTION (10) The elements of this matrix are

We suppose that an anti-reflection coating at the pump wavelength is added to the Bragg mirror. The nonlinear coupling coefficient is now zero and the parametric interaction matrix for the counter-propagating wave is then (17) In (15), the self-consistency matrix is given by

(11) (18) In (11), we have left the possibility of a reflected pump field, with a related nonlinear coupling coefficient given by in which is the right mirror complex reflectivity at the pump wavelength (see Fig. 1), and stands for the possible change, both in sign and modulus, of the nonlinear at reflection. Using the GaAs wafer, we coefficient . have The change of variable between the rotating phase referential and the propagating waves is now

with

(12)

Finally, the boundary conditions are given by the reflectivities at the different Bragg mirrors

where

(19) and are the total while mirror phases of the signal and the idler waves, respectively. Now, the self-consistency (16) reads

and for which, given the relation may be worked out into its imaginary and real parts as

(20) , (21)

(13) where the reflectivity matrixes are

(22)

(14)

. In the case of , (21) and (22)

where we recall that a balanced DROPO [12], i.e., become mod

and are the complex reflectivities ( ) at the right and left Bragg mirrors. respectively.

(23) (24)

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is also easily obtainable from (21) and (22) but is cumbersome and does not bring any new physics. However, a few related results are of some interest. For instance, the derivative shows that detuned of this general expression relative to solutions from exact double resonance exist but display a higher threshold. The linearised variation of the threshold condition near double resonance is given by (29)

Fig. 2. When the nonlinear cavity thickness equals one coherence length of the desired parametric interaction, these parametric interactions add up coherently in the nonlinear cavity.

These results are somewhat similar to the ones obtained by Falk in his study of doubly resonant OPO instabilities [13]. The main difference is that, in our case, these above expressions are that is dominated by the phase mismatch terms . We now investigate the necessary conditions for parametric oscillations in GaAs microcavities. Clearly, phase condition (21) is fulfilled for the double condi: this is the exact double resonance case [12]. tion In that case, the threshold condition on the gain (22) is given by (25) This latter expression is an implicit function which allows to . compute the threshold gain for a given phase mismatch Straightforward algebra shows that the necessary threshold gain is minimum when the following condition is fulfilled:

so that small deviations from double resonance may indeed be accepted. However, the threshold condition may become unattainable far away from double resonance, as can be clearly . observed in (24) in a balanced DROPO when IV. CAVITY DESIGN OF A MICROCAVITY GAAS OPO From all the above results, the design rules of the microcavity for minimum threshold power now clearly follows. First, the mirror phases have to be optimized so that the stamay be fulfilled for a tionary phase condition ) thanks to expressions (19). given set of wavelengths ( for minimum threshold Then, the optimum cavity lengths are calculated from conditions (26) and (27); that is (30) is the generwhere alized finesse of a double resonant cavity [see (27)]. One immediately sees that condition (30), indeed, yields for high cavity finesse . This condition, together with photon energy conservation

(26) (31) Let us note that, in our case, the phase mismatch is far larger than the parametric gain. This latter expression can thus be , that is when the cavity approximated as thickness is an odd number of phase-mismatch lengths. A schematic interpretation of this condition is given in Fig. 2. Injecting optimum condition (26) into the threshold (25), one immediately finds that the minimum gain is given by

determine unique sets of solutions. In other words, for a given pump wavelength and a given GaAs cavity thickness, only given pairs of signal and idler photons may be produced which are given by (30) and (31). The minimum threshold power is then given by the expression (27); that is

(27)

(32)

which, for the special case of a balanced OPO, is (28) This latter expression is particularly illuminating: in case the parametric gain could be comparable to the phase-mismatch (typically 10 cm for m m generawavevector tion in GaAs), we could reach oscillations for very small values of . But this is an almost impossible task to perform in semiconductors. The role of the high mirror reflectivities is thus to toward reasonable limits. decrease the value of Away from the exact double resonance case, the general exas a function of the detuning pression for the threshold

The phase of the Bragg mirrors have then to be calculated such that the phase condition is fulfilled. Since the phase mis, match is far higher than the parametric gain (7b) together with (19) show that exact double resonance is and obtained for the total mirror phases : these latter conditions are nothing else than the usual stationary phase conditions for the signal and idler waves, respectively. Fig. 3 shows the idler wavelengths which can be generated—i.e., for which the optimum phase-matching condition (30) with photon energy conservation (31) is obtained—as a function of the GaAs cavity thickness for different possible of values of the pump wavelength, with a cavity finesse


Fig. 3. Idler wavelength which can be optimally generated in a GaAs nonlinear microcavity as a function of the microcavity thickness and for different pump wavelengths. These optimum thicknesses are an even number of the desired parametric interaction. of coherence lengths 3

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(a)

(b)

Fig. 4. Threshold power of the optimum h110i GaAs nonlinear microcavity (see Fig. 3) as a function of the desired idler wavelength and for different pump wavelengths. The mirror reflectivities for the signal and idler waves are 99.9% and 99.2%, respectively.

492. This figure clearly shows that these cavities are ideal for 8–12- m OPO generation. The Sellmeir equation for GaAs are the ones published by Adashi [14]. This figure shows that, in so far as the mirror phases can be worked out properly, large uncertainties of the GaAs cavity thickness can be accepted thanks to a variation of the pump wavelength. Fig. 4 shows now the threshold pump intensity necessary to obtain GaAs microcavities (for which parametric oscillations in pm/V [15]) for various values of the ( ) pairs obtained through Fig. 3. Calculations are done for exact double resonance condition [condition (25)] with Bragg mirror reflecand of 99.5% and 99.2%, respectively. These tivities reflectivities yield a cavity finesse of 492, making the GaAs threshold parametric gain in the 3 cm [(28)], which is a very reasonable value. These threshold values are far below the published values of damage threshold in GaAs, which means that OPO oscillations should be feasible in GaAs microcavities [9].

Fig. 5. (a) Schematic view of a semi-monolithic microcavity in which the exact double resonance of the signal and idler waves can be easily obtained. (b) Threshold parametric gain in a h110i GaAs microcavity necessary for oscillation on either side of the optimum, i.e. = 10:6 m.

V. SPECTRAL BEHAVIOR OF A MICROCAVITY GAAS OPO Thus far, we have investigated the optimization of the cavity parameters in order to obtain minimum threshold. We are now in the position to study the behavior of a nonlinear microcavity of a given length when pumped at a given wavelength . From ), only all the possible couples of resonant wavelengths ( those which satisfy the exact double-resonance conditions and will oscillate. This double-resonance condition is, however, very difficult to obtain [8], [16]–[18]. Indeed, let us take a GaAs wafer thickness in 195- m range (adapted 10 m emission, see Fig. 3). With the above suggested for and free spectral mirror reflectivities, the cavity finesses are in the 626 and 391, 7.8 cm and 7.7 cm , ranges of yielding overwhelmingly small Fabry-Perot linewidths and 19 10 cm for the signal and idler 12 10 cm waves respectively. In order to study the parametric gain bandwidth, we thus suppose that once the signal resonance is obtained, the idler mirror

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Fig. 7. Same as Fig. 2, but with a constructive pump reflection.

(a)

(b) Fig. 6. (a) Schematic view of a monolithic microcavity at exact double resonance. Giordmaine-Miller diagram of the idler and signal wave resonance curves in a h i GaAs microcavity. (b) The mode overlap integrals are indi: m. cated by hollow circles (normalized to the maximum value at

110

= 9 88

can be systematically tuned into resonance. For this, we thus assume, in a first approach, that only the mirror for the signal wave is an epitaxially grown Bragg mirror with, for instance, : technologically, the signal Bragg a phase mirror is indeed the thinner and thus the easiest mirror to grow. On the other hand, the idler mirror phase is assumed to be tunable; for instance, the mirror is a classical dielectric coating, e.g., on a ZnSe substrate, placed on a piezo very near the wafer surface [semi monolithic structure shown in Fig. 5(a)]. For clarity’s sake, we neglect optical effects related to the GaAs/air interface. One can thus independently satisfy the exact double-resoare given nance condition. The allowed signal wavelengths , where is an integer. by the sole condition for each mode is then The threshold parametric gain . Fig. 5(b) the solution of the implicit (25) with shows the variation of the threshold parametric gain as a function of the idler wavelength: one observes that this variation is very small. It means that, with this experimental situation, the parametric gain bandwidth of the system is quite large. This is

Fig. 8. Influence of the right mirror reflectivity at the pump wavelength on the microcavity oscillation threshold. Three cases are illustrated: no pump reflection, pure-phase matching (PPM), and opposite-phase matching (OPM). . Pump intensity reflection on the right mirror is R

= 30%

not surprising since, in the mid-infrared, GaAs displays a very small dispersion. Finally, we discuss the case of a monolithic microcavity, with an epitaxially deposited mirror for the signal wave [19], and a dielectric coating highly reflecting for the idler wave [see Fig. 6(a)]. We are left with the classical problem in doubly resonant OPO (DROPO) of finding the threshold of partially overlapping modes in the parametric gain bandwidth [10], [18]. In Fig. 6(b), we show the Giordmaine-Miller plot of a 195.2- m GaAs nonlinear cavity (optimized for near 10- m optimum idler generation) pumped by a 2- m laser beam. The exact cavity length and couples of generated wavelengths ) are given by the condition that is a rational ( number [18]. On the same plot, we show the mode overlap m integral normalized to its maximum value at (hollow circles). This figure clearly shows that, due to the high cavity finesses, it is indeed rather tricky to obtain exact double resonance for a specific case. On the other hand, away from the exact coincidence [18], the mode overlap integral decreases drastically, which means that the nonlinear microcavity will be intrinsically single-longitudinal mode.


VI. CONCLUSION We have investigated the conditions necessary for optical parametric oscillation in an isotropic semiconductor microcavity. The conditions obtained are tractable and physically sound, leading to optimization design rules. For instance, one of the design rules is that the wafer thickness should be as close as possible to an odd number of phase-mismatch lengths of the desired parametric interaction. It is shown that, in GaAs wafers, for instance, oscillation thresholds far below optical damage threshold can be envisioned for reasonable Bragg mirror reflectivities. The experimental difficulty will lie in the exact double resonance condition for the idler and signal waves simultaneously. In addition, like in the laser, an optimum reflectivity for the output mirror should be found to optimize the idler energy out coupling; work is in progress to clarify this point. Once these difficulties are solved, these microcavities should be ideal sources in the 8–12- m infrared range.

constructively on their way back to the left mirror. Fig. 7 gives a schematic interpretation of this condition. Indeed, the Taylor expansion of order 2 of the self-consistency matrix defined as a function of in (15) is then given by (35), shown at the bottom of the page. Those equations are particularly illuminating in the case of . The equations are then a balanced DROPO, i.e., if similar to those obtained when there is no pump reflection, prois done. Two parviding that the change and ticularly simple cases can then be pointed out, . . Equation (27) giving the Let us first consider that minimum threshold gain can then be written as

where In the case of opposite phase matching (OPM), , which is obviously the worst case here; the minimum threshold gain is

APPENDIX INFLUENCE OF PUMP REFLECTION We investigate here the case of a nonzero pump reflection . Parametric interaction between the at the right mirror: three waves can then occur in the left direction, which will either enhance or diminish the global conversion efficiency, depending on the relative phase between all the waves. We first introduce , the cumulated differential phase shift of the three waves just after reflection on the right mirror

with

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(33)

Let us now consider the exact double resonance case, for which we already demonstrated minimum threshold gain in the case of no pump reflection and providing condition (26). We are going to extend this result, taking into account the pump reflection. , we recall that the cavity satisfies First, since condition (30) together with

(34) Condition (30) stands for optimum conversion from pump to signal and idler waves for a path length . Thanks to pump reflection, this conversion can be even more efficient for a round trip of the waves in the cavity: we are going to show that , in the pure-phase matching situation this is when (PPM). The waves that are generated after reflection are then in phase with the ones generated before. They thus interfere

where Fig. 8 is drawn on the same principle as Fig. 4, i.e. it shows the threshold pump intensity necessary to obtain parametric osGaAs microcavities for different values of cillations in ) pairs obtained through Fig. 3. But we now consider the ( the following three cases: 1) no pump reflection; 2) pump reflection with PPM; and 3) and pump reflection with OPM. This clearly illustrates the influence of pump reflection on the OPO threshold. REFERENCES [1] J. A. Armstrong et al., “Interactions between light waves in a nonlinear dielectric,” Phys. Rev., vol. 127, pp. 1918–1939, 1962. [2] G. Boyd and C. Patel, “Enhancement of optical second-harmonic generation by reflection phase matching in ZnSe and GaAs,” Appl. Phys. Lett., vol. 8, pp. 456–459, 1966. [3] E. Rosencher, Toward Integrated Semiconductor Optical Parametric Oscillators, ser. Série IV. Paris, France: C. R. Academy of Science, 2000, vol. T.1, pp. 615–625. [4] A. Fiore et al., “Phase matching using an isotropic nonlinear otpical materials,” Nature, vol. 391, pp. 463–466, 1998. [5] E. Lallier et al., “Infrared difference frequency generation with quasiphase-matched GaAs,” Electron. Lett., vol. 17, pp. 212–213, 1998. [6] L. Becouarn et al., “Second harmonic generation of a CO2 laser using a thick quasiphase matched GaAs layer grown by hydide vapor phase epitaxy,” Electron. Lett., vol. 34, p. 1500, 1998. [7] E. Rosencher, B. Vinter, and V. Berger, “Second harmonic generation in nonbirefringent semiconductor microcavities,” J. Appl. Phys., vol. 78, p. 6042, 1995.

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[8] C. Simmonneau et al., “Second-harmonic generation in a doubly resonant semiconductor microcavity,” Opt. Lett., vol. 22, pp. 1775–1777, 1997. [9] R. Haïdar et al., “Largely tunable mid-infrared (8–12 m) difference frequency generation in isotropic semiconductors,” J. Appl. Phys., vol. 91, pp. 2550–2552, 2002. [10] S. J. Bosnan and R. L. Byer, “Optical parametric oscillator threshold and linewidth studies,” IEEE J. Quantum Electron., vol. QE-15, pp. 415–431, June 1979. [11] E. Rosencher and B. Vinter, Optoelectronics. New York: Cambridge Univ. Press, 1998. [12] E. Rosencher and C. Fabre, “Oscillation characteristics of continuous wave optical parametric oscillators: Beyond the mean field approximation,” J. Opt. Soc. Amer. B. [13] J. Falk, “Instabilities in the doubly resonant parametric oscillator: A theoretical analysis,” IEEE J. Quantum Electron., vol. QE-7, pp. 230–235, June 1971. [14] S. Adashi, “GaAs, AlAs and AlxGa1-xAs: Material parameters for use in a research and device application,” J. Appl. Phys., vol. 58, p. R1, 1985. [15] I. Shoji et al., “Absolute scale of second-order nonlinear-optical coefficients,” J. Opt. Soc. Amer. B, vol. 14, pp. 2268–2294, 1997. [16] V. Berger, “Second harmonic generation in monolithic cavities,” J. Opt. Soc. Amer. B, vol. 14, no. 6, pp. 1351–1360, 1997. [17] S. T. Yang, R. C. Eckardt, and R. L. Byer, “Power and spectral characteristics of continuous wave parametric oscillators: The doubly to singly resonant transition,” J. Opt. Soc. Amer. B, vol. 10, no. 9, pp. 1684–1695, 1993. [18] B. Scherrer et al., “Dual-cavity doubly resonant optical parametric oscillators: Demonstration of pulsed single—Mode operation,” J. Opt. Soc. Amer. V, vol. 17, no. 10, pp. 1716–1729, 2000. [19] R. Haïdar et al., “Monolithic Optical Parametric Oscillator Using Semiconductor Cavities MOPOSC—Final Report,” European project, ONERA, Ref.: RTS 2/06 136 DMPH, 2002.

Riad Haïdar was born in Dakar, Sénégal, in 1974. He graduated from Ecole Supérieure d’Optique, Orsay, France, in 1999. He is currently working toward the Ph.D. degree, majoring in quasiphase matched optical frequency conversion in isotropic semiconductors, at Université Paris Sud, Orsay, France In 2000, he joined Prof. Rosencher’s team at the French aerospace agency Office National d’Etudes et des Recherches Aerospatiales (ONERA), Palaiseau Cedex, France.


Nicolas Forget was born in Paris, France, in 1977. He graduated from Ecole Polytechnique, Palaiseau, France, in 2001, where he is currently working toward the Ph.D. degree, majoring in chirped pulse optical parametric amplification. In 2002, he joined Prof. Rosencher’s team at the French aerospace agency Office National d’Etudes et des Recherches Aerospatiales (ONERA), Palaiseau Cedex, France.

Emmanuel Rosencher (SM’94) was born in Paris, France, in 1952. He graduated from the Ecole Polytechnique, Paris, France, in 1975, and from the Ecole Nationale Supérieure des Télécommunications, Paris, France, in 1977. He received the Doctorat in Applied Mathematics from the Université de Paris IX in 1978 and the Habilitation Degree in Physics from the Université de Grenoble in 1986. From 1978 to 1988, he was with the Centre National d’Etudes des Télécommunications (CNET), Grenoble, France. In 1984, he discovered the transistor effect in the monolithic Si/CoSi =Si heterostructure and studied the related metal base transistor devices, as well as the quantum transport in ultra-thin epitaxial metal film. In 1988, he joined the Laboratoire Central de Recherches de THOMSON-CSF, Orsay, France, as the Head of the Physics Laboratory. In 1989, he discovered the giant optical nonlinear effects in asymmetrical quantum wells. In 1998, he joined the Office National d’Etudes et des Recherches Aerospatiales (ONERA), Palaiseau Cedex, France, where he is currently the Director of the Physics Branch (which contains 420 persons). He is also an Associate Professor of physics at the Ecole Polytechnique. He is a pioneer in the physics of intersubband transitions in semiconductor quantum wells, optical nonlinearities in semiconductors, and optical parametric oscillators. He has authored the physics textbook Optoelectronics (Cambridge, U.K.: Cambridge University Press, 2002) as well as books for the popularization of science, including La Puce et l’Ordinateur (Paris, France: Flammarion, 1995), translated in Italian, Spanish, and Portuguese. He has published more than 250 papers in the field of semiconductor heterostructures, nonlinear optics, and laser physics, with 140 papers in refereed international reviews and 70 invited talks. He also holds 15 patents. Dr. Rosencher received the 1991 Prix Foucault (Physique Appliquée) from the Société Française de Physique, the Montgolfier Award 2000 (Arts Physiques) from the Société d’Encouragement de l’Industrie Nationale, the 2001 Arnulf-Françon Prize from the Société Française d’Optique, and he is Chevalier de l’Ordre National du Mérite. He is Fellow of the Optical Society of America (OSA) and of the Institute of Physics (IoPF96), and a member of the French and American Physics Societies.