Nanogap experiments for laser cooling - A progress report

Ryan P. Martin, Josef Velten, Andreas Stintz, Kevin J. Malloy, Richard I. Epstein, Mansoor Sheik-Bahae, Michael P. Hasselbeck, Babak Imangholi, S. T.P. Boyd, Todd M. Bauer

Research output: Chapter in Book/Report/Conference proceedingConference contribution

7 Scopus citations


One of the challenges of laser cooling a semiconductor is the typically high index of refraction (greater than 3), which limits efficient light output of the upconverted photon. This challenge is proposed to be met with a novel concept of coupling the photon out via a thin, thermally insulating vacuum gap that allows light to pass efficiently by frustrated total internal reflection. This study has the goal of producing a test structure that allows investigation of heat transport across a "nanogap" consisting of a thin film supported over a substrate by an array of nanometer-sized posts. The nanogap is fabricated monolithically by first creating a film of SiO2 on a silicon substrate, lithographically defining holes in the SiO2, and covering this structure including the holes with silicon. Selective lateral etching will then remove the SiO2, leaving behind a thin gap between two Si layers spaced apart by nanometer-scale Si posts. Demonstration of this final step by successfully undercutting the a-Si upper layer due to the hydrophobic nature of silicon and the slow etch rate of buffered oxide etch in the small gap has proved to be problematic. Arriving at a feasible solution to this conundrum is the current objective of this project in order to begin investigating the thermal conductivity properties of the structure.

Original languageEnglish (US)
Title of host publicationLaser Cooling of Solids
StatePublished - 2007
Externally publishedYes
EventLaser Cooling of Solids - San Jose, CA, United States
Duration: Jan 24 2007Jan 25 2007

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherLaser Cooling of Solids
Country/TerritoryUnited States
CitySan Jose, CA


  • Frustrated internal reflection
  • Laser cooling
  • MEMS technology

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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