scholarly journals Effects of Size and Surrounding Medium on Whispering-Gallery-Mode Lasers in Er3+-Doped Silica Microspheres

Author(s):  
Thu Trang Hoang ◽  
Van Dai Pham ◽  
Thanh Son Pham ◽  
Xuan Bach Nguyen ◽  
Khai Q. Le ◽  
...  

Abstract This work reports the experimental fabrication and characterization of the Er3+-doped silica microspheres (mS) and numerical investigation of the effects of size and surrounding medium on the optical properties of whispering-gallery-mode (WGM) lasers. The heat melting method of two discharge electrodes was used to produce the Er3+-doped silica mSs of diameters up to several tens of micrometers. The 125-mm diameter single-mode optical fiber was tapered with a cone angle formed by chemical etching in hydrofluoric acid (HF) solutions. It was used to produce the mSs and couple the pumped laser into mS surface as well was coupled out the lasing emission. The WGM lasers at telecom regime of ~1520-1570 nm were characterized in both clockwise (CW) and counterclockwise (CCW) propagation directions. By adjusting the coupling gap between the tapered optical fiber and the mS surface, the selectivity of the multi- or single-emitted modes of the mS laser was achieved. We performed finite-difference time-domain (FDTD) simulations to examine the size dependence and analyze the effect of the surrounding medium’s refractive index on the optical characteristics, such as emission wavelength, intensity, as well as the shape of WGM lasing emission. The facile approach and quantitative investigation of this work has attracted much attention from researchers in the micro-photonic field and may be useful in many applications from tunable single-mode lasing sensing to optical micro-devices.

1995 ◽  
Vol 20 (8) ◽  
pp. 813 ◽  
Author(s):  
N. Dubreuil ◽  
J. C. Knight ◽  
D. K. Leventhal ◽  
V. Sandoghdar ◽  
J. Hare ◽  
...  

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jie Liao ◽  
Lan Yang

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.


2009 ◽  
Vol 17 (4) ◽  
pp. 2573 ◽  
Author(s):  
Judith R. Schwesyg ◽  
Tobias Beckmann ◽  
Anne S. Zimmermann ◽  
Karsten Buse ◽  
Daniel Haertle

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Chia-Chin Chiang ◽  
Jian-Cin Chao

An optical fiber solution-concentration sensor based on whispering gallery mode (WGM) is proposed in this paper. The WGM solution-concentration sensors were used to measure salt solutions, in which the concentrations ranged from 1% to 25% and the wavelength drifted from the left to the right. The experimental results showed an average sensitivity of approximately 0.372 nm/% and anR2linearity of 0.8835. The proposed WGM sensors are of low cost, feasible for mass production, and durable for solution-concentration sensing.


2021 ◽  
Author(s):  
Minghong Xie ◽  
Wenxiao Gong ◽  
Lei Kong ◽  
Yang Liu ◽  
Yang Mi ◽  
...  

Abstract Perovskite nanocrystals (NCs) have emerged as attractive gain materials for solution-processed microlasers. Despite the recent surge of reports in this feld, it is still challenging to develop low-cost perovskite NCbased microlasers with high performance. Herein, we demonstrate low-threshold, spectrally tunable lasing from ensembles of CsPbBr3 NCs deposited on silica microspheres. Multiple whispering-gallery-mode lasing is achieved from individual NC/microspheres with a low threshold of ∼3.1 µJ cm−2 and cavity quality factor of ∼1193. Through time-resolved photoluminescence measurements, electron-hole plasma recombination is elucidated as the lasing mechanism. By tuning the microsphere diameter, the desirable single-mode lasing is successfully achieved. Remarkably, the CsPbBr3 NCs display durable room-temperature lasing under ∼107 shots of pulsed laser excitation, substantially exceeding the stability of conventional colloidal NCs. These CsPbBr3 NC-based microlasers can be potentially useful in photonic applications.


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