Selective Pump Focusing on Individual Laser Modes in Microcavities

Abstract

We demonstrate selective pump focusing for highly isolated single-mode lasers in microdisk and microring cavities, and achieve lasing action from a microdisk cavity underneath a scattering medium. The spatial profile of the pumping light evolves by an iterative feedback process and is optimized to maximize the field overlap with a selected cavity mode. The high order of mode selectivity and high resolving power are obtained in a multimode cavity in the presence of significant modal overlaps. As a result of the adaptive optical pumping, we successfully achieve the efficient energy transfer to a microdisk underneath a random scattering medium and observe lasing action through the scattering medium. We believe that our selective pumping procedure will pave the way for the development of low-threshold, single-mode nanolasers embedded in various materials.

Localized modes revealed in random lasers

“…This method has been successfully demonstrated experimentally to select modes in a weakly scattering random laser [30], in a micro-disk laser [31] and in asymmetric resonant cavities [32]. It was also proposed to control spectral characteristic [29,30,33], laser power efficiency [34], emission directionality [31,35], laser threshold [36], and modal interactions [37,38]. Here, we apply this method to select lasing modes individually and image them spatially.…”

Electrically Driven Micro- and Nano-Scale Semiconductor Light Sources

“…In addition, the pump efficiency is impractically low for small and/or asymmetrical optical cavities (e.g., one-dimensional (1D) photonic crystals (PhCs), nanowires (NWs), nanotubes (NTs), and waveguide cavities). Although there are some advanced techniques to spatially modulate the shape of an excitation beam for controlled and adaptive pumping, it requires another complicated optical setup [8][9][10]. Furthermore, the simultaneous excitation of multiple light sources over a large area in a single chip is inherently impossible, which can seriously limit the key functions of integrated circuits (e.g., WDM).…”

Flexible Manipulation of Lasing Modes in an Erbium-Doped Microcavity via an Add–Drop Configuration

“…Lasing mode manipulation is highly desirable, such as single-mode lasing emission, , suppression of lasing modes, selectivity of lasing wavelength, , and controllable vortex lasing generation . Meanwhile, selective emission of lasing modes, especially single-mode lasing emission, is of importance for optical communications.…”

“…14−19 Rare earth elements have captured much interest because of the large quantum efficiency and ease of emitting in the infrared wavelength band. 20 Lasing mode manipulation is highly desirable, such as singlemode lasing emission, 21,22 suppression of lasing modes, 23 selectivity of lasing wavelength, 24,25 and controllable vortex lasing generation. 26 Meanwhile, selective emission of lasing modes, especially single-mode lasing emission, is of importance for optical communications.…”

“…26 Meanwhile, selective emission of lasing modes, especially single-mode lasing emission, is of importance for optical communications. Up to now, there are several proposed schemes, which realized mode manipulation of WGM lasing and even single-mode lasing emission, such as spatial pump engineering, 21,22 loss engineering, 23 parity-time symmetric coupled cavities, 27 and cavity size engineering. 28 However, these proposed methods have disadvantages, such as sacrificed Q factors induced by the decreased cavity size or lack of flexibility.…”