Highly-sensitive anisotropic porous silicon based optical sensors

Jesús Álvarez*, Paolo Bettotti, Neeraj Kumar, Isaac Suárez, Daniel Hill, Juan Martínez-Pastor

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review


The modeling, fabrication and characterization of PSi fabricated from both (110) and (100) surface oriented silicon for optical sensing is thoroughly reported. First, based on the generalized Bruggeman method, the birefringence and sensitivity of the fabricated membranes were calculated as a function of the fabrication parameters such as porosity and pore sizes; and external effects, such as the pores surface oxidation. Thereafter we report on the fabrication of PSi membranes from (110) and (100) surface oriented silicon with pore sizes in the range of 50-80 nm, and the characterization of their birefringence using a polarimetric setup. Their sensitivities were determined by filling the pores with several liquids having different refractive index. As a result, sensitivities as high as 1407 nm/RIU were obtained for the (110) samples at a 1500 nm wavelength and 382 nm/RIU for the (100) samples at the same wavelength.

Original languageEnglish
Article number821209
JournalProceedings of SPIE - International Society for Optical Engineering
Publication statusPublished - 31 Jan 2012
EventFrontiers in Biological Detection: From Nanosensors to Systems IV - San Francisco, CA, United States
Duration: 21 Jan 201222 Jan 2012

Bibliographical note

Copyright 2012 SPIE. One print or electronic copy may be made for personal use only. Systematic reproduction, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.


  • birefringence
  • optical sensor
  • phase retardation
  • Porous silicon


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