Yijun Xie | University of Colorado, Boulder (original) (raw)

Papers by Yijun Xie

Progress in Quantum Electronics

Optical frequency comb, with precisely controlled spectral lines spanning a broad range, has been... more Optical frequency comb, with precisely controlled spectral lines spanning a broad range, has been the key enabling technology for many scientific breakthroughs. In addition to the traditional implementation based on modelocked lasers, photonic frequency microcombs based on dissipative Kerr and quadratic cavity solitons in high-Q microresonators have become invaluable in applications requiring compact footprint, low cost, good energy efficiency, large comb spacing, and access to nonconventional spectral regions. In this review, we comprehensively examine the recent progress of photonic frequency microcombs and discuss how various phenomena can be utilized to enhance the microcomb performances that benefit a plethora of applications including optical atomic clockwork, optical frequency synthesizer, precision spectroscopy, astrospectrograph calibration, biomedical imaging, optical communications, coherent ranging, and quantum information science.

This document provides supplementary information to "Time-magnified photon counting with a 550-fs... more This document provides supplementary information to "Time-magnified photon counting with a 550-fs resolution," https://doi.org/10.1364/OPTICA.420816. It consists of four sections: 1. TM-TCSPC schematic diagram; 2. Resolving sub-ps pulsewidth change with TM-TCSPC; 3. ToF image and signal processing; and 4. Photon pileup effect. 1. TM-TCSPC schematic diagram Fig. S1. The schematic diagram for the TM-TCSPC. SUT, signal under test; SPAD, single-photon avalanche diodes.

OSA Nonlinear Optics 2021, 2021

Sub-hertz fundamental linewidth soliton microcombs consisting of multiple eigenmodes are demonstr... more Sub-hertz fundamental linewidth soliton microcombs consisting of multiple eigenmodes are demonstrated in an ultra-high-Q graded-index fiber FP microresonator. The feedback-free SBS-assisted comb generation and stabilization enables ultralow-noise microwave generation.

Optics Letters, 2021

Kerr microcombs hold the promise of bringing frequency combs onto the chip and into a variety of ... more Kerr microcombs hold the promise of bringing frequency combs onto the chip and into a variety of applications requiring low size, weight, power, and cost. However, reliable Kerr microcomb generation is hindered by the thermal effect and multistability of dissipative Kerr solitons (DKSs). Past approaches toward Kerr microcomb reliability include either deterministic single-soliton generation or self-starting soliton behavior but not both. Here we describe a regime of DKSs that is both deterministic and self-starting, in which only a single soliton can stably exist. We term this new DKS regime “monostable DKSs” (MS-DKSs) as all other optical behaviors, such as continuous-wave-only and multiple solitons, are fundamentally forbidden by the design. We establish a graphical model to describe MS-DKSs and discuss the design principles of MS-DKSs. We numerically demonstrate the MS-DKS behavior in an example periodically poled lithium niobate microring resonator.

Conference on Lasers and Electro-Optics, 2021

500-fs temporal resolution is achieved in time-correlated single photon counting for the first ti... more 500-fs temporal resolution is achieved in time-correlated single photon counting for the first time with the assistance of a fiber parametric time magnifier. Time-of-flight depth imaging of a glass sample is demonstrated with 75-μm resolution.

Mode-lockin o find a bidirecti andomly rotate nidirectional mo rection. Then, fi directional mod ... more Mode-lockin o find a bidirecti andomly rotate nidirectional mo rection. Then, fi directional mod om scratch, such kes less than on identified, bidir ver weeks.

Nanophotonics, 2021

We theoretically study the nature of parametrically driven dissipative Kerr soliton (PD-DKS) in a... more We theoretically study the nature of parametrically driven dissipative Kerr soliton (PD-DKS) in a doubly resonant degenerate micro-optical parametric oscillator (DR-DμOPO) with the cooperation of χ (2) and χ (3) nonlinearities. Lifting the assumption of close-to-zero group velocity mismatch (GVM) that requires extensive dispersion engineering, we show that there is a threshold GVM above which single PD-DKS in DR-DμOPO can be generated deterministically. We find that the exact PD-DKS generation dynamics can be divided into two distinctive regimes depending on the phase matching condition. In both regimes, the perturbative effective third-order nonlinearity resulting from the cascaded quadratic process is responsible for the soliton annihilation and the deterministic single PD-DKS generation. We also develop the experimental design guidelines for accessing such deterministic single PD-DKS state. The working principle can be applied to different material platforms as a competitive ultr...

Optica, 2020

The bidirectional mode-locked oscillator is an emerging light source architecture suitable for du... more The bidirectional mode-locked oscillator is an emerging light source architecture suitable for dual-comb applications. Therein, bidirectional mode-locked fiber lasers (MLFLs) are particularly promising for their cost effectiveness, system compactness, and environmental robustness. However, the pulse energy has been limited to tens of picojoules, restricting practical dual-comb applications, especially in the nonlinear regime. In this paper, we break the pulse energy limit by devising the first bidirectional all-normal dispersion MLFL with an artificial saturable absorber (ASA). Bidirectional dissipative solitons are generated with > 5 -THz bandwidths and > 1 -nJ pulse energies. Free-running laser performance is extensively characterized, and the physical mechanism for bidirectional ASA mode-locking is studied. Last but not least, a proof-of-concept dual-comb spectroscopy measurement is demonstrated. Our work paves the way for a new class of bidirectional MLFLs benefiting dual-...

Optica, 2021

Time-correlated single-photon counting (TCSPC) is an enabling technology for applications such as... more Time-correlated single-photon counting (TCSPC) is an enabling technology for applications such as low-light fluorescence lifetime microscopy and photon counting time-of-flight (ToF) 3D imaging. However, state-of-the-art TCSPC single-photon timing resolution (SPTR) is limited to 3–100 ps by single-photon detectors. Here, we experimentally demonstrate a time-magnified TCSPC (TM-TCSPC) that achieves an ultrashort SPTR of 550 fs with an off-the-shelf single-photon detector. The TM-TCSPC can resolve ultrashort pulses with a 130-fs pulse width difference at a 22-fs accuracy. When applied to photon counting ToF 3D imaging, the TM-TCSPC greatly suppresses the range walk error that limits all photon counting ToF 3D imaging systems by 99.2% and thus provides high depth accuracy and precision of 26 µm and 3 µm, respectively.

Journal of Crystal Growth, 2017

Although many new scintillation materials are developed, CsI: Tl is still prevailing because of i... more Although many new scintillation materials are developed, CsI: Tl is still prevailing because of its high scintillation efficiency. In this work, CsI: Tl thin films were fabricated by vacuum thermal evaporative deposition method and their morphology properties and growth orientation were observed by SEM and XRD. Photoluminescent spectra were used to measure the luminescent properties of the CsI: Tl thin film. The results show us the film formation process of CsI: Tl thin film and analyze the effect of film formation process and the deposition rate on the orientation of the CsI: Tl thin film.

Light: Science & Applications

Optical frequency combs in microresonators (microcombs) have a wide range of applications in scie... more Optical frequency combs in microresonators (microcombs) have a wide range of applications in science and technology, due to its compact size and access to considerably larger comb spacing. Despite recent successes, the problems of self-starting, high mode efficiency as well as high output power have not been fully addressed for conventional soliton microcombs. Recent demonstration of laser cavity soliton microcombs by nesting a microresonator into a fiber cavity, shows great potential to solve the problems. Here we study the dissipative soliton generation and interaction dynamics in a microresonator-filtered fiber laser in both theory and experiment. We bring theoretical insight into the mode-locking principle, discuss the parameters effect on soliton properties, and provide experimental guidelines for broadband soliton generation. We predict chirped bright dissipative soliton with flat-top spectral envelope in microresonators with normal dispersion, which is fundamentally forbidden...