Soft‐Lithographed Up‐Converted Distributed Feedback Visible Lasers Based on CdSe–CdZnS–ZnS Quantum Dots

Abstract

The development of a solution-deposited up-converted distributed feedback laser prototype is presented. It employs a sol-gel silica/germania soft-lithographed microcavity and CdSe-CdZnS-ZnS quantum dot/sol-gel zirconia composites as optical gain material. Characterization of the linear and nonlinear optical properties of quantum dots establishes their high absorption cross-sections in the one-and two-photon absorption regimes to be 1 × 10 −14 cm 2 and 5 × 10 4 GM, respectively. In addition, ultrafast transient absorption dynamics measurements of the graded seal quantum dots reveal that the Auger recombination lifetime is 220 ps, a value two times higher than that of the corresponding CdSe core. These factors enable the use of such quantum dots as optically pumped gain media, operating in the one-and two-photon absorption regime. The incorporation of CdSe-CdZnSZnS quantum dots within a zirconia host matrix affords a quantum-dot ink that can be directly deposited on our soft-lithographed distributed feedback grating to form an all-solution-processed microcavity laser.

Active photonic devices based on colloidal semiconductor nanocrystals and organometallic halide perovskites

“…Thresholds of stimulated emission were found to be between 0.15 and 1.4 mJ/cm 2 under 1 PA, and 7 and 19.8 mJ/cm 2 and TPA. Later the same authors made a similar comparison with CdSe/ CdZnS/ZnS QDs, and demonstrated the generation ASE under TPA with a threshold of 12.8 mJ/cm 2 [56]. In both cases, results were obtained under femtosecond excitation.…”

“…Thresholds between 0.15 mJ/cm 2 (625 nm) and 1.4 mJ/cm 2 (547 nm) under femtosecond excitation were obtained. Finally, the same authors demonstrated ASE with a threshold as low as 0.15 mJ/cm 2 by using a CdSe/CdZnS/ZnS QDs embedded in ZrO 2 [56].…”

“…This structure consists of a diffraction grating where the period of the grating matches the Bragg condition (λ/2n, where n is the effective refractive index). A similar design was proposed in [56] with a close packed film of CdSe/CdZnS/ZnS QDs (emission between 630 and 655 nm) embedded in a ZrO 2 matrix. The waveguide was optically pumped at 400 nm and 800 nm with femtosecond pulses in order to compare the generation of lasing under one photon and the two photon absorption mechanisms.…”

Low Threshold, Amplified Spontaneous Emission from Core‐Seeded Semiconductor Nanotetrapods Incorporated into a Sol–Gel Matrix

“…Nearly identical energy spacings between the two ASE transitions were found in fi lms of the same tetrapods but with different thicknesses, thus excluding the possibility that the higher energy ASE transition is due to a broad gain profi le coupled to different waveguide modes. [ 24 ] An analysis of its PL intensity as a function of pump power revealed that the threshold for the higher energy ASE transition was approximately 2 times that of the biexcitonic ASE. A similar observation was previously reported for CdSe/ZnS NCs in titania matrices where a higher energy ASE peak at large pump intensities was ascribed to stimulated emission originating from a non-degenerate CdSe …”

CdS_xSe_1-x/ZnS semiconductor nanocrystal laser with sub 10kW/cm^2 threshold and 40nJ emission output at 600 nm

“…By adjusting their mean size and/or their semiconductor composition, they can be made to emit light efficiently across a wide range of wavelengths [2]. They can be combined with both organic and inorganic materials to form composites and, e.g., can be patterned by soft lithography [3,4]. In turn, CQDs are finding applications in biological imaging, optoelectronics [5][6][7][8][9][10][11][12][13][14] and have also great potential as a laser material [15][16][17][18][19][20][21][22][23][24].…”