Lab‐on‐Fiber Based on Optimized Gallium Selenide for Femtosecond Mode‐Locked Lasers and Fiber‐Compatible Photodetectors

Abstract

Although the physicochemical properties of gallium selenide (GaSe) have been widely investigated, the property and application exploration of GaSe‐coupled fiber devices are still in its infancy. There are obvious challenges, namely, selecting from multiple GaSe phases and effectively coupling to the unique fiber structure. Herein, lab‐on‐fiber (LOF) based on optimized GaSe is proposed to be used for robust femtosecond pulse generation and fiber‐compatible photodetection. First, based on density functional theory (DFT) calculations, ε‐GaSe is selected as a preferable model material for its suitable band structures, low work function, and high damage threshold. Benefiting from the fiber‐compatible ε‐GaSe combined with micro–nano processing, stable femtosecond soliton pulse (≈303 fs, 16.67 MHz, 51.64 dB) output and multiwavelength (520, 808, and 1550 nm) detection are realized in LOF. These results pave the way for optics research of polyphase semiconductors and design of integrated all‐fiber devices.

A Systematic Study of the Temperature Dependence of the Dielectric Function of GaSe Uniaxial Crystals from 27 to 300 K

“…Gallium selenide (GaSe) is a compound in the III-VI group that has gained considerable interest recently due to its exceptional properties and potential applications in various fields including photodetectors [1][2][3][4][5][6], water splitting [6][7][8], lasers [9][10][11][12], and nonlinear optics [13][14][15]. GaSe can crystallize in four different polytypes, namely β-, ε-, γ-, and δ-phase structures, which correspond to the space groups P6 3 /mmc (D 4 6h ), P6m2(D 1 3h ), R3m (C 5 3v ), and P6 3 mc (C 4 6v ), respectively.…”

The Wannier-Mott Exciton, Bound Exciton, and Optical Phonon Replicas of Single-Crystal GaSe

“…It consists of vertically stacked tetralayers of Se-Ga-Ga-Se, which are held together by van der Waals forces. This compound possesses exceptional properties that have contributed to advancements in photodetectors [1][2][3][4][5][6], water splitting [6][7][8], lasers [9][10][11][12], and nonlinear optics [13][14][15]. The various stacking sequences of the tetralayers give rise to different polytypes, including β-, ε-, γ-, and δphase structures.…”

Wafer‐Scale Two‐Dimensional Semiconductors for Deep UV Sensing

“…[5,11,12] Within this wide class of materials, metal chalcogenide (MC) III-VI compounds are of great interest due to their unique properties, spanning from high mobility carriers and tunable band structures to nonlinear optical responses and ferroelectricity. [13][14][15][16][17][18][19][20][21] In particular, for single-layer and few-layer MCs, the valence band (VB) is shaped like an inverted Mexican hat with van Hove singularities (vHs) in the density of states (DoS) and hole effective masses much heavier than in traditional semiconductors. [22][23][24][25][26][27] The interest in this unusually shaped band is motivated by the possibility to create in a semiconductor new forms of magnetic order, charge density waves, and superconductivity driven by weakly screened electron correlations.…”