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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Microlens array fabricated by a low-cost grayscale lithography maskless system

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Autor(es):
Aristizabal, Sergio Lopera [1] ; Cirino, Giuseppe Antonio [2] ; Montagnoli, Arlindo Neto [2] ; Sobrinho, Aparecido Arruda ; Rubert, Jose Benaque [2] ; Hospital, Michel ; Mansano, Ronaldo Domingues [1]
Número total de Autores: 7
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Dept Engn Eletr, LSI PSI, Sao Paulo - Brazil
[2] Univ Fed Sao Carlos, Dept Engn Eletr, BR-13560 Sao Carlos, SP - Brazil
Número total de Afiliações: 2
Tipo de documento: Artigo Científico
Fonte: Optical Engineering; v. 52, n. 12 DEC 2013.
Citações Web of Science: 14
Resumo

This work presents the fabrication of a contiguous f/\# = f/15 Fresnel microlens array (MLA) by employing a low-cost home-built maskless exposure lithographic system based on a digital light projector technology by using Texas Instruments' digital micromirror device chip. A continuous diffractive phase relief structure was generated on a photoresist-coated silicon wafer, replicated in polydimethylsiloxane (PDMS) and electrostatically bonded to a glass substrate. The whole exposure time takes 10.8 min to expose a 2.4 x 2.4 mm MLA, with a resolution of 2.5 mu m. This exposure time is relatively short, enabling high throughput or fast prototyping. Optical characterization was carried out using a He-Ne laser source (lambda = 633 nm), by evaluating the maximum intensity of each spot generated at the MLA focal plane, Imax, as well as its sharpness by measuring their full width at half maximum (FWHM) intensity values. The resulting FWHM and maximum intensity spot average values were FWHMAVG = 20 +/- 8% mu m and Imax(AVG) = 0.71 +/- 7% a.u:, respectively. The quality of replication was evaluated by profile characterization of the resulting mold and replica based on step height measurement along 180 mu m. The maximum obtained difference was 32 nm, corresponding to 2.5% of the total mold height or lambda/20. AFM measurements were also carried out to quantify the roughness quality between mold and replica. The resulting RMS roughness was 4.73 nm (lambda/130) and 6.66 nm (lambda/95) for mold and replica, respectively. A comparison between theoretical and measured intensity profiles at the MLA focal plane was also carried out. A good correspondence between the results was found. Such an MLA can be applied as a Shack-Hartmann wavefront sensor in optical interconnects and to enhance the efficiency of detector arrays. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE) (AU)

Processo FAPESP: 08/57862-6 - NAMITEC
Beneficiário:Jacobus Willibrordus Swart
Linha de fomento: Auxílio à Pesquisa - Temático
Processo FAPESP: 08/57858-9 - Instituto Nacional de Óptica e Fotônica
Beneficiário:Vanderlei Salvador Bagnato
Linha de fomento: Auxílio à Pesquisa - Temático
Processo FAPESP: 98/02755-7 - Processos de corrosão por plasma para a fabricação de microelementos ópticos difrativos
Beneficiário:Giuseppe Antonio Cirino
Linha de fomento: Bolsas no Brasil - Doutorado