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Nonlinear Enhancement of Optical Spectroscopy in the Mid-infrared


Liu, Mingchen (2024) Nonlinear Enhancement of Optical Spectroscopy in the Mid-infrared. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/ffd0-yq96.


Optical spectroscopy has long been a cornerstone in studying material properties, playing a pivotal role in the advancement of science and technology. It remains crucial in both research and industry, particularly in the mid-infrared (MIR) region, known for its unique molecular fingerprint capabilities. The emergence of optical frequency comb technology has set the stage for dual-comb spectroscopy (DCS) to revolutionize optical spectroscopy with its potential superiority in speed, resolution, sensitivity, precision, and compactness. However, practical implementation of DCS in the MIR region faces challenges due to its demanding requirements for sources, inefficient photodetection, and dynamic range limitations, despite an exciting prospect. This dissertation explores the use of quadratic optical nonlinearity to tackle these challenges. By manipulating energy and information flows between photons of different frequencies through nonlinear optics, we leverage well-developed near-infrared (NIR) sources, detectors, and optics to address difficulties in the MIR region. We first demonstrate optical parametric oscillators in the regime of simulton (quadratic soliton pair), achieving a high-power broadband MIR frequency comb with a remarkably high NIR-to-MIR power conversion efficiency. We also introduce cross-comb spectroscopy (CCS), which upconverts the MIR frequency comb to the NIR region and allows MIR spectral analysis with NIR photodetection. This novel approach can offer superior signal-to-noise ratio (SNR), dynamic range, and detection efficiency compared to conventional DCS, while providing wavelength flexibility. Additionally, we present a new method to facilitate the detection of trace samples with short-pulse optical parametric amplifiers, which can significantly enhance SNR and limit of detection of existing methods. Overall, this research demonstrates the capabilities of quadratic nonlinearity in enabling high-performance optical sensing in spectral regions where sources, detectors, and optics are less developed.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:nonlinear optics, ultrafast optics, frequency comb, mid-infrared, optical parametric oscillator, quadratic soliton, dual-comb spectroscopy, background-free spectroscopy, rotational–vibrational spectroscopy
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Electrical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Marandi, Alireza
Thesis Committee:
  • Okumura, Mitchio (chair)
  • Wang, Lihong
  • Yang, Changhuei
  • Marandi, Alireza
Defense Date:19 January 2024
Funding AgencyGrant Number
Air Force Office of Scientific Research (AFOSR)FA9550-20-1-0040
National Science Foundation (NSF)1846273
Record Number:CaltechTHESIS:03252024-002457591
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for ch.2 adapted for ch.3 adapted for ch.4 and ch. 5 paper related to ch.2 paper related to ch.2 paper related to ch.4 and ch.5 paper related to ch.4 and ch.5
Liu, Mingchen0000-0002-0649-8976
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16341
Deposited By: Mingchen Liu
Deposited On:27 Mar 2024 21:41
Last Modified:03 Apr 2024 20:28

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