Tunable WGM Laser Based on the Polymer Thermo-Optic Effect

Abstract

In this work, the thermo-optic effect in polymers was used to realize a temperature-tunable whispering-gallery-mode laser. The laser was fabricated using a capillary tube filled with a light-emitting conjugated polymer solution via the capillary effect. In the whispering-gallery-mode laser emission wavelength can be continuously tuned to about 19.5 nm using thermo-optic effect of polymer. The influence of different organic solvents on the tuning rate was studied. For a typical lasing mode with a bandwidth of 0.08 nm, a temperature-resolved tuning rate of ~1.55 nm/°C was obtained. The two-ring coupling effect is responsible for the suppression of the WGM in the micro-cavity laser. The proposed laser exhibited good reversibility and repeatability as well as a sensitive response to temperature, which could be applied to the design of photothermic and sensing devices.

Self-Aligned Emission of Distributed Feedback Lasers on Optical Fiber Sidewall

“…It can be seen that the lasing wavelength changes slightly with the ambient temperature. The lasing wavelength shifts from 636.9 to 634.8 nm when the temperature changes from 25 to 50 • C. The variation of the lasing peak can be attributed to the thermo-optic effect of the polymer [36]. On the whole, the stability of the laser performance is acceptable for most potential applications.…”

An all-optical tunable polymer WGM laser pumped by a laser diode

“…The spacing between adjacent mode clusters Δ λ is 1.56 nm caused by the two-ring coupling effect. 20 The capillary tube consists of two mismatched cylinder microrings, forming a coupled asymmetric microcavity, which causes inhibition between the two nearby ring microcavities. Fig.…”

“…In recent years, various geometries of polymer lasers have received signicant attention, such as Fabry-Perot structures, 11 distributed feedback structures, [12][13][14] photonic crystals, 15,16 and whispering-gallery-mode (WGM) cavities. [17][18][19][20] However, a significant limitation of the current polymer lasers is the optical pump source. More recently, polymer lasers have been optically pumped by laser diodes (LDs) or by light emitting diodes, [21][22][23][24][25][26] optimizing the compact and undoubtedly low-cost polymer laser systems, which greatly promotes their applicability.…”

“…Zhang et al have reported a tunable WGM laser based on the polymer thermo-optic effect. 20 Beneting from the strong thermo-optic effect of polymers, the emission wavelength can be continuously tuned to about 19.5 nm as the temperature changes from 24 C to 42.2 C. Niu et al have proposed a tunable polymer WGM laser pumped by a laser diode. 23 By changing the concentration of the gain material, the laser wavelength is tuned over 15 nm.…”

Pressure-based fast tuning of high-Q crystalline whispering gallery mode resonator

“…However, fast and wide-range tuning is challenging for crystalline resonators 16 . Currently, the most widely used tuning method is thermo-optic tuning, 17 , 18 which is applicable to WGM resonators of various materials and shapes. However, thermo-optic tuning requires controlling the external temperature of the WGM resonator, 19 resulting in a relatively slow tuning process, which cannot satisfy the demand for high response speed.…”