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ScienceDirect Physics Procedia 73 (2015) 82 – 86
4th h International Confereence Photon nics and Info formation Optics, O PhIO O 2015, 28-330 January 2015 2
D Direct laaser reco ording onn amorph hous siliicon film m Askar Kutanov K *,, Igor Snim mshikov, Nurbek N Sydyk uluu Institute of Phyysical-Technical Problems and Material M Science, National Academy A of Scien nces, Chuy prosppect 265-a, Bishkeek 720071, Kyrgy yz Republic
Absttract Resu ults of direct lasser recording onn amorphous siilicon film by llaser with waveelength Ȝ= 532 nm and Blu Raay single modee laser diodee with Ȝ= 405 nnm are presenteed. Measuremen nts of a-silicon film transmissiion spectrum beefore and after exposure by fo ocused laserr beam demonsttrates its changing. It proves th he refractive inndex changing of o recording lay yer under laser radiation interaaction of amorphous silicon to crysttalline silicon uunder laser radiation interaction. Measuremeent of recorded relief and transformation t show ws that under laaser radiation innteraction to a-ssilicon layer rellief depth is abo out 30-100 nm. Microstructurees with a size of o 5–7 ȝm are a recorded byy 120mW singlle mode Blu Ray R laser diode with Ȝ= 405 nm. n Use of Blu Ray laser dioddes for recording on amorrphous silicon ffilm opens oppportunities to deesign compact Laser Writing System for difffractive structuures fabrication and interfference lithograaphy. © Published by Elsevier B.V.B.V. This is an open access article under the CC BY-NC-ND license ©2015 20 015The TheAuthors. Authorrs. Published byy Elsevier (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer--review under rresponsibility of the National Research R Nucleear University MEPhI M (Moscow w Engineering PPhysics Institutte). Peer-review under responsibility of the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) Keyw words: direct laserr recording; amorrphous silicon film m; Blu Ray laser ;
1. In ntroduction Direct D laser reecording on amorphous a sillicon film is aattractive for diffractive sttructures recoording withou ut wet chem mical processiing and it brinng new possib bilities of difffractive structtures fabrication with the uuse of laser writing w deviice [Poleshchuuk et al. (2010)] . Example of widely uused simple diffractive d stru uctures is antiireflective coaatings baseed on subwavee gratings [Scchopf et al. (1998)] with a period of app proximately half of the lighht wavelength h. The use of high-speed scanning systems s of in nterference litthography (SIILs) [Poleshcchuk et al. (22005); Kutanov & mshikov (2011)] forming diffractive d strructures by coonsecutive wrriting of mod derate-size fraagments or ceells is Snim expeecting to assisst in solving thhe problem off deposition off antireflectiv ve diffractive coatings c onto large-size surrfaces
* Corresponding C autthor. Tel.: +996 312 3 392 057; fax:+996 312 6462955. E-mail E address:
[email protected]
1875-3892 © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) doi:10.1016/j.phpro.2015.09.125
Askar Kutanov et al. / Physics Procedia 73 (2015) 82 – 86
of solar s panels. E Early, we dem monstrated direect laser recorrding of dot ho olograms on amorphous a sillicon film by pulsed p UV V laser with Ȝ= = 355 nm [K Kutanov & Sniimshikov (20 11)]. This pap per present reesults of reseaarch on direct laser reco ording on amoorphous silicoon film using green g laser (Ȝ= = 532 nm) and d single mode laser diode w with Ȝ= 405 nm m. 2. Measurement M t of absorptioon spectrum for f amorphou us silicon film m on glass sub bstrate Two-beam T speectrophotomeeter PYE UNIICAM is usedd to measure spectrum s of absorption a forr amorphous silicon s layeer on glass suubstrate. The spectrums of amorphous ssilicon film ab bsorption depend on wavellength for diffferent thicckness are shoown on (Fig. 1).
Fig. 1. Absoorption spectrums of amorphous ssilicon film depen nd on wavelength h for different thickness (d1= =0.15ȝm, d2=0.3 ȝm, d3= 0.4 ȝm m and d4= 1 ȝm)
One O can see thhat maximum m of light absorrption for amoorphous silico on layer is for wavelength raange of 340… …360 nm.. Early, we deemonstrated poossibility of dot holograms recording on a-silicon film using pulse U UV-laser with h Ȝ= 355 5 nm [Kutanovv & Snimshikoov (2011)]. Fiig. 2 shows phhoto of grating g, recorded on n amorphous ssilicon film on n glasss substrate byy pulse UV-laaser with Ȝ= 35 55 nm with puulse energy 0.10 ȝJ.
Fig. 2. Photoo of the surface reelief of dot hologrram recorded by pulse p UV-laser (Ȝ Ȝ= 355 nm) on a-Sii film
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For F different aapplications itt is interesting g to explore ddirect laser reecording on a-silicon film for exposing laser radiaation with Ȝ= 405 nm ( Bluu Ray laser dio ode) and with green laser (ȜȜ= 532 nm) on n Polar Coordi dinate Laser Paattern Generator for Fabbrication of Diffractive D Optical O Elemennts with Arbiitrary Structu ure [Poleshchuuk et al. (199 99)] . m absorption spectrum s befoore (red curvee) and after (blue curve) exxposure by foccused Meaasurements off a-silicon film laserr radiation (ȜȜ= 532 nm) shown on Fiig.3 demonstrrates that aftter exposure by focused llaser radiation n the abso orption spectruum is changinng. It proves th he refractive inndex changing for recordin ng medium aftter interaction n with laserr radiation.
Fig. 3. Measuurements of a-silicon film absorptiion spectrum befo ore (red curve) an nd after (blue curve) expo osure by focused laser radiation (ȜȜ= 532 nm)
3. Ex xperiment on n direct recorrding on amo orphous silicoon by single mode m Blu Ray y laser diode ȜȜ= 405nm For F direct recoording on amoorphous silicon n Mitsubishi 120mW singlle mode Blu Ray R laser diodde was used. Laser L beam m is collimateed by aspheric lens after laaser diode annd then it focu used by micro o objective too recording media. m Com mputer controols laser pulsse duration and a their freqquency. Fig. 4 shows pho oto taken froom microscop pe in transsmitted light for spots(a) and lines(b) recorded by single mode Blu Ray laseer diode on aa-Si film on glass subsstrate. In n order to meeasure the deppth of the reliief recording on amorphou us silicon film m sample was performed on the interrference scannning white ligght microscop pe VLI in reeflection mode. Measuremeent of recordded relief on Fig.5 show wed that under the interactiion of laser raadiation to thee amorphous silicon s film the relief formeed with heightt 30 100 nm. The T drawback of single modde laser diode used for expeeriments was a short length of coherence and it depend dence from m output radiaation power. It was difficu ult to record bby Blu Ray laser dot holog grams for fabbrication of master m matrrix hologram for embossinng holograms reproduction.. Therefore, itt will be usefful to have Bllu Ray laser diode d with h the greater leength of coherrence.
Askar Kutanov et al. / Physics Procedia 73 (2015) 82 – 86
Fig. 4. Phootos of spots(a) an nd lines(b) recordded on amorphouss silicon by single e mode laser diode withh Ȝ= 405 nm
Fig. 5. Measuring relief form mation under foccused laser (Ȝ= 40 05 nm) beam interaction to asilicon layer witth volume increassing. Relief amplitude is ~100 nm.
4. Conclusions C It’s I shown thaat under interaaction of a-Si film by focussed laser beam m the local cry ystallization aappears and reelief is form ms with depthh ~30-100 nm m. Measuremen nts of absorpttion spectrum m demonstrated d that amorphhous silicon laayer’s reflex index is chhanging after exposure by focused laserr beam. It mak kes attractive use of directt laser recordiing on orphous silicoon for securityy applicationss. Direct laserr recording on n amorphous silicon by sinngle mode Blu u Ray amo laseer diode Ȝ= 4005nm was deemonstrated. Use U of single mode Blu Raay laser diodees opens oppoortunities to design d com mpact laser devvice for diffraactive structures fabricationn for different application. Ack knowledgemeents We W express grratitude to Proof. A.Poleshchuk, Head off the Diffractiv ve Optics Lab boratory, Instiitute of Autom matics and d Electrometryy, Novosibirsk, Russia and d Dr. T. Dohhi, President of o Optiworks Ltd., Japan for support of o this reseearch. Refferences Kutaanov, A., Snimshiikov, I., 2011. Dirrect laser recordin ng of dot holograams on a-Si film/// Proceeding Optiics Photonics Jappan, pp. 30aCS2. Poleshchuk, A., Churrin, E., Koronkevvich, V., et al., 19 999. Polar coordiinate laser pattern n generator for fa abrication of difffractive optical ellements with w arbitrary struucture. Applied Optics, O 38(8), pp.1 1295-1301.
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Askar Kutanov et al. / Physics Procedia 73 (2015) 82 – 86 Poleshchuk, A., Kutanov, A., Bessmeltsev, V., et al., 2010. Microstructuring of optical surfaces: Technology and device for direct laser writing of diffractive structures, Optoelectronics, Instrumentation and Data Processing 46.2, pp.171-180. Poleshchuk, A., Kutanov, A., Malishev, A., et al., 2005. High-speed laser writing system for diffractive optical elements and dot matrix holograms fabrication. In Diffractive Optics: Meeting, Warsaw, Poland, September 3, Vol. 7. Schopf, R., Hultsch, T., Lotz, J., et al., 1998. Antireflective submicrometer surface-relief gratings for solar applications, Solar Energy Materials and Solar Cells, 54(1), pp.333-342.
