Sub-nominal resolution Fourier transform spectrometry with chip-based combs

Fuente: arXiv
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Main Authors: Sterczewski, Lukasz A., Bagheri, Mahmood
Format: Preprint
Published: 2023
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author Sterczewski, Lukasz A.
Bagheri, Mahmood
author_facet Sterczewski, Lukasz A.
Bagheri, Mahmood
contents Chip-based optical frequency combs address the demand for compact, bright, coherent light sources of equidistant phase-locked lines. Traditionally, the Fourier Transform Spectroscopy (FTS) technique has been considered a suboptimal choice for resolving comb lines in chip-based sensing applications due to the requirement of long optical delays, and spectral distortion from the instrumental line shape. Here, we develop a sub-nominal resolution FTS technique that precisely extracts the comb's offset frequency in any spectral region directly from the measured interferogram without resorting to nonlinear $f$-to-$2f$ interferometry. This in turn enables MHz-resolution spectrometry with millimeter optical retardations. Low-pressure MHz-wide absorption lines probed by widely-tunable chip-scale mid-infrared OFCs with electrical pumping are fully resolved over a span of tens of nanometers. This versatile technique paves the way for compact, electrostatically-actuated, or even all-on-chip high-fidelity FTS, and can be readily applied to boost the resolution of existing commercial instruments several hundred times.
format Preprint
id arxiv_https___arxiv_org_abs_2303_13074
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Sub-nominal resolution Fourier transform spectrometry with chip-based combs
Sterczewski, Lukasz A.
Bagheri, Mahmood
Optics
Instrumentation and Detectors
Chip-based optical frequency combs address the demand for compact, bright, coherent light sources of equidistant phase-locked lines. Traditionally, the Fourier Transform Spectroscopy (FTS) technique has been considered a suboptimal choice for resolving comb lines in chip-based sensing applications due to the requirement of long optical delays, and spectral distortion from the instrumental line shape. Here, we develop a sub-nominal resolution FTS technique that precisely extracts the comb's offset frequency in any spectral region directly from the measured interferogram without resorting to nonlinear $f$-to-$2f$ interferometry. This in turn enables MHz-resolution spectrometry with millimeter optical retardations. Low-pressure MHz-wide absorption lines probed by widely-tunable chip-scale mid-infrared OFCs with electrical pumping are fully resolved over a span of tens of nanometers. This versatile technique paves the way for compact, electrostatically-actuated, or even all-on-chip high-fidelity FTS, and can be readily applied to boost the resolution of existing commercial instruments several hundred times.
title Sub-nominal resolution Fourier transform spectrometry with chip-based combs
topic Optics
Instrumentation and Detectors
url https://arxiv.org/abs/2303.13074