Controllable Growth of Aligned Monocrystalline CsPbBr₃ Microwire Arrays for Piezoelectric‐Induced Dynamic Modulation of Single‐Mode Lasing

Abstract

Since the appearance of semiconductor solid-state lasers in the 1960s, [1] lasers have shown tremendous potential in various applications, such as data communication, medical treatment, environmental science, and military defense. Up to now, enormous research efforts have been conducted to develop high-quality semiconductor lasers. [2] Multiple-mode lasers suffer from false signaling, random fluctuation, and instability which hinder their practical applications. [3,4] Therefore, efforts to achieve single-mode lasers have drawn much attention due to the monochromaticity, high stability, controllable output wavelength, and great potential of these lasers in practical applications, such as in on-chip optical communication. [5] Thus far, most single-mode lasers have been realized in the following four ways: 1) decreasing the cavity size to enlarge the free spectral range (FSR); [6,7] 2) fabricating distributed Bragg reflector (DBR) mirror structures or distributed feedback (DFB) CsPbBr 3 shows great potential in laser applications due to its superior optoelectronic characteristics. The growth of CsPbBr 3 wire arrays with well-controlled sizes and locations is beneficial for cost-effective and largely scalable integration into on-chip devices. Besides, dynamic modulation of perovskite lasers is vital for practical applications. Here, monocrystalline CsPbBr 3 microwire (MW) arrays with tunable widths, lengths, and locations are successfully synthesized. These MWs could serve as high-quality whispering-gallery-mode lasers with high quality factors (>1500), low thresholds (<3 µJ cm −2 ), and long stability (>2 h). An increase of the width results in an increase of the laser quality and the resonant mode number. The dynamic modulation of lasing modes is achieved by a piezoelectric polarization-induced refractive index change. Single-mode lasing can be obtained by applying strain to CsPbBr 3 MWs with widths between 2.3 and 3.5 µm, and the mode positions can be modulated dynamically up to ≈9 nm by changing the applied strain. Piezoelectric-induced dynamic modulation of single-mode lasing is convenient and repeatable. This method opens new horizons in understanding and utilizing the piezoelectric properties of lead halide perovskites in lasing applications and shows potential in other applications, such as on-chip strain sensing.

Amplified Spontaneous Emission and Lasing in Lead Halide Perovskites: State of the Art and Perspectives

“…Finally, almost aligned CsPbBr 3 microwire WGM lasers were recently realized by a PDMS template-confined antisolvent crystallization method, obtaining a good control of wire length, width and position [61]. Strain induced dynamic modulation of the lasing modes was also demonstrated and ascribed to piezoeletric polarization effects on the CsPbBr 3 gain region and refractive index.…”

Metal Halide Perovskite Arrays: From Construction to Optoelectronic Applications

“…demonstrated a single‐mode WGM laser array based on the CsPbBr 3 MWs. [ 31 ] As shown in Figure 16e, with increasing the optical excitation up to the thresholds, the transition from spontaneous emission to stimulated emission occurred, leading to a single sharp peak that grew rapidly with further pump density increasing. By plotting the PL intensity as a function of pump density, an inflection point, which is the threshold, was obtained in this process, and full‐width at half‐maximum (FWHM) experienced a sharp decrease after this point (Figure 16f).…”

Recent advances in hybrid perovskite nanogenerators

“…The piezoelectric polarization effect has been demonstrated in CsPbBr 3 nanowires which can induce refractive index change and enable dynamic modulation of lasing modes. 70 Lately, CsPbBr 3 polycrystalline films were employed as piezoelectric materials in PENGs for electromechanical energy-harvesting and current-sensing applications. 71 The morphology of CsPbBr 3 films was initially optimized with the processing parameters, and a highly effective piezoelectric coefficient of 40.3 pm/V was recorded at a subsequent poling field.…”