On-chip random spectrometer

B. Redding; S. F. Liew; R. Sarma; H. Cao

doi:10.1117/12.2050021

21 May 2014 On-chip random spectrometer

B. Redding, S. F. Liew, R. Sarma, H. Cao

Proceedings Volume 9101, Next-Generation Spectroscopic Technologies VII; 910105 (2014) https://doi.org/10.1117/12.2050021
Event: SPIE Sensing Technology + Applications, 2014, Baltimore, MD, United States

Abstract

Spectrometers are widely used tools in chemical and biological sensing, material analysis, and light source characterization. The development of a high-resolution on-chip spectrometer could enable compact, low-cost spectroscopy for portable sensing as well as increasing lab-on-a-chip functionality. However, the spectral resolution of traditional grating-based spectrometers scales with the optical pathlength, which translates to the linear dimension or footprint of the system, which is limited on-chip. In this work, we utilize multiple scattering in a random photonic structure fabricated on a silicon chip to fold the optical path, making the effective pathlength much longer than the linear dimension of the system and enabling high spectral resolution with a small footprint. Of course, the random spectrometer also requires a different operating paradigm, since different wavelengths are not spatially separated by the random structure, as they would be by a grating. Instead, light transmitted through the random structure produces a wavelengthdependent speckle pattern which can be used as a fingerprint to identify the input spectra after calibration. In practice, these wavelength-dependent speckle patterns are experimentally measured and stored in a transmission matrix, which describes the spectral-to-spatial mapping of the spectrometer. After calibrating the transmission matrix, an arbitrary input spectrum can be reconstructed from its speckle pattern. We achieved sub-nm resolution with 25 nm bandwidth at a wavelength of 1500 nm using a scattering medium with largest dimension of merely 50 μm.

Citation Download Citation

B. Redding, S. F. Liew, R. Sarma, and H. Cao "On-chip random spectrometer", Proc. SPIE 9101, Next-Generation Spectroscopic Technologies VII, 910105 (21 May 2014); https://doi.org/10.1117/12.2050021

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
7 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Spectroscopy

Scattering

Light scattering

Waveguides

Photonic crystals

Calibration

Sensors

Show All Keywords

Keywords/Phrases

Search In:

Publication Years