scholarly journals Single-mode characteristic of a supermode microcavity Raman laser

2021 ◽  
Vol 118 (22) ◽  
pp. e2101605118
Author(s):  
Pei-Ji Zhang ◽  
Qing-Xin Ji ◽  
Qi-Tao Cao ◽  
Heming Wang ◽  
Wenjing Liu ◽  
...  
Keyword(s):  
Raman Laser ◽  
Single Mode ◽  
Light Sources ◽  
Dual Mode ◽  
Stimulated Scattering ◽  
Whispering Gallery ◽  
Mode Suppression ◽  
Counterpropagating Waves ◽  
Mode Characteristic ◽  
Side Mode

Microlasers in near-degenerate supermodes lay the cornerstone for studies of non-Hermitian physics, novel light sources, and advanced sensors. Recent experiments of the stimulated scattering in supermode microcavities reported beating phenomena, interpreted as dual-mode lasing, which, however, contradicts their single-mode nature due to the clamped pump field. Here, we investigate the supermode Raman laser in a whispering-gallery microcavity and demonstrate experimentally its single-mode lasing behavior with a side-mode suppression ratio (SMSR) up to 37 dB, despite the emergence of near-degenerate supermodes by the backscattering between counterpropagating waves. Moreover, the beating signal is recognized as the transient interference during the switching process between the two supermode lasers. Self-injection is exploited to manipulate the lasing supermodes, where the SMSR is further improved by 15 dB and the laser linewidth is below 100 Hz.

Stable Single-mode 20-channel Uniform Buried Grating DFB QCL Array Emitting at ~8.3 μm

2021 ◽  
Author(s):  
Fan Ye ◽  
Fengmin Cheng ◽  
Zhiwei Jia ◽  
JinChuan Zhang ◽  
Ning Zhuo ◽  
...  
Keyword(s):  
Peak Power ◽  
Room Temperature ◽  
Tuning Range ◽  
Single Mode ◽  
Edge Mode ◽  
Quantum Cascade ◽  
Mode Suppression ◽  
Pulsed Mode ◽  
Side Mode ◽  
Front Facet

Abstract A 20-channel distributed feedback (DFB) quantum cascade laser (QCL) arrays based on uniform buried grating have been demonstrated. In pulsed mode, peak power reaches 80 mW and slope efficiency reaches 167 mW/A for 2.5-mm-long laser in the arrays at room temperature. The loss difference of two band-edge mode increases when reflectivity of the front facet becomes small, which prevents the mode hopping. The device shows linear tuning after the anti-reflectivity coating is deposited in the front facet, maintaining peak power of 64 mW. The whole chip covers a tuning range of 64 cm-1, centering at 8.3 μm, with side-mode-suppression-ratio over 20 dB at room temperature.

Side-mode suppression in ultraviolet quasi-semicircle microlaser cavity

2020 ◽  
Vol 34 (30) ◽  
pp. 2050330
Author(s):  
Canran Zhang ◽  
Gangyi Zhu ◽  
Siqing He ◽  
Jun Dai
Keyword(s):  
Near Field ◽  
Distribution Patterns ◽  
Mode Competition ◽  
Optically Pumped ◽  
Optical Resonance ◽  
Whispering Gallery ◽  
Mode Suppression ◽  
Resonance Modes ◽  
Optical Modes ◽  
Side Mode

We report a quasi-semicircle GaN ultraviolet microcavity laser. Poincaré map of the quasi-semicircle cavity shows periodic, quasi-periodic and chaotic optical trajectories. Finite-element-method optical near-field distribution patterns of the periodic optical modes agree with the optical loops in the quasi-semicircle cavity. Based on the numerical results, optically pumped lasing experiment shows that ultraviolet multimode lasing action from different optical resonance modes can be effectively stimulated at low pumping intensity in the quasi-semicircle GaN cavity, and the side-mode suppression phenomenon can be obtained at high pumping intensity. Because the possible period optical loops are quasi-periodic and unstable, the quasi-whispering-gallery mode lasing with higher quality factor prefer to dominate the lasing action under high pumping. The experimental and simulated lasing modes suggest that side-mode suppression phenomenon can be caused by the mode competition between quasi-whispering-gallery modes and other quasi-periodic modes.

scholarly journals Исследование спектров генерации арочных квантово-каскадных лазеров

2020 ◽  
Vol 128 (6) ◽  
pp. 696
Author(s):  
А.В. Бабичев ◽  
Д.А. Пашнев ◽  
Д.В. Денисов ◽  
А.Г. Гладышев ◽  
Ю.К. Бобрецова ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Quantum Cascade Lasers ◽  
Single Mode ◽  
Lasing Wavelength ◽  
Quantum Cascade ◽  
Mode Suppression ◽  
Ring Diameter ◽  
Solid Alloys ◽  
Cascade Lasers ◽  
Side Mode

The results of studying the temperature characteristics of arched quantum-cascade lasers of 7-8 μm spectral range with different geometric sizes are presented. Laser heterostructure was grown by molecular beam epitaxy. The active region consisted of 50 cascades based on heteropairs of solid alloys In0.53Ga0.47As/Al0.48In0.52As. Single-mode lasing was demonstrated for lasers with a half-ring diameter of 100 μm and a length of linear section of 1 mm. The maximum side-mode suppression ratio at a temperature of 290 K was 26 dB, the lasing wavelength was 7.73 μm.

scholarly journals Optical whispering-gallery mode barcodes for high-precision and wide-range temperature measurements

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jie Liao ◽  
Lan Yang
Keyword(s):  
High Precision ◽  
Dynamic Range ◽  
Single Mode ◽  
Whispering Gallery Mode ◽  
Temperature Measurements ◽  
Laser Source ◽  
Multiple Modes ◽  
Whispering Gallery ◽  
Wide Range ◽  
Thermal Sensing

AbstractTemperature is one of the most fundamental physical properties to characterize various physical, chemical, and biological processes. Even a slight change in temperature could have an impact on the status or dynamics of a system. Thus, there is a great need for high-precision and large-dynamic-range temperature measurements. Conventional temperature sensors encounter difficulties in high-precision thermal sensing on the submicron scale. Recently, optical whispering-gallery mode (WGM) sensors have shown promise for many sensing applications, such as thermal sensing, magnetic detection, and biosensing. However, despite their superior sensitivity, the conventional sensing method for WGM resonators relies on tracking the changes in a single mode, which limits the dynamic range constrained by the laser source that has to be fine-tuned in a timely manner to follow the selected mode during the measurement. Moreover, we cannot derive the actual temperature from the spectrum directly but rather derive a relative temperature change. Here, we demonstrate an optical WGM barcode technique involving simultaneous monitoring of the patterns of multiple modes that can provide a direct temperature readout from the spectrum. The measurement relies on the patterns of multiple modes in the WGM spectrum instead of the changes of a particular mode. It can provide us with more information than the single-mode spectrum, such as the precise measurement of actual temperatures. Leveraging the high sensitivity of WGMs and eliminating the need to monitor particular modes, this work lays the foundation for developing a high-performance temperature sensor with not only superior sensitivity but also a broad dynamic range.

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