Multi-wavelength colloidal quantum dot lasers in distributed feedback cavities

Abstract

Lasers with multi-wavelength colloidal quantum dots (CQDs) can be achieved using complex grating structures and flexible substrate. The structure contains graduated periods and rectangular cavity fabricated through interference lithography, which acts as the distributed feedback cavity. A layer of densely packed CQD film is deposited on the cavity via spin coating technique. The performance of CQD lasers based on different distributed feedback cavities is investigated. Multi-wavelength lasing is achieved based on a flexible rectangular cavity.

Single-Mode Lasing in Polymer Circular Gratings

“…the coupling between the Bragg diffraction from the periodic structures (circular and regular) and waveguide (F8BT film) mode [23,39]. From the Figure 4a, it can be seen that by increasing the angle with a step of o 45 there is no change in the extinction curves.…”

“…Extinction spectrum for both the circular and regular gratings (one dimension, 1D) covered with a gain material F8BT can be achieved from the formula , where and indicate the intensities of the transmitted spectrum, as shown in the curves of Figure 4 a,b. The wide peaks in both the Figure 4 a,b correspond to absorption spectrum of the conjugated polymer F8BT, whereas the narrow peaks show the coupling between the Bragg diffraction from the periodic structures (circular and regular) and waveguide (F8BT film) mode [ 23 , 39 ]. From the Figure 4 a, it can be seen that by increasing the angle with a step of 45° there is no change in the extinction curves.…”

“…Therefore, all these unique and intriguing features of the conjugated polymers provide a new route to explore optoelectronic technologies and micro-cavity lasers [ 14 , 15 ]. In recent years, conjugated polymers have been extensively applied as gain mediums in laser systems with different optical feedback nanostructures, such as whispering gallery mode (WGM)[ 16 , 17 ], micro-droplet [ 18 ], and distributed feedback (DFB) cavities [ 19 , 20 , 21 , 22 , 23 ]. Modern research considers many conjugated polymers in lasing applications, such as poly [9, 9-dioctylfluorenyl-2,7-diyl]–end capped with DMP (PFO), poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(1,4-benzo-(2,1′,3) -thiadiazole)] (F8BT), and poly[2 -methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) covering the whole visible spectra, which can generate coherent light either pump optically or electrically [ 24 , 25 , 26 ].…”

Large-Area Biocompatible Random Laser for Wearable Applications

“…The biocapacity of the heterogeneous film is important for wearable sensors, which can potentially be used on human skin, such as the finger, to detect vital signs and monitor secreted sweat levels [ 12 , 13 ]. Random lasers based on localized surface plasmon resonance (SPR) of noble metallic nanoparticles have been reported in both thin films and solutions by researchers [ 14 , 15 , 16 , 17 , 18 , 19 ]. Hrelescu.…”

Low-Threshold Microlasers Based on Holographic Dual-Gratings

“…Different types of gain materials have been applied to microcavity lasers, including dyes, polymers, and colloidal quantum dots (CQDs) [1][2][3][4][5][6]. CQDs have demonstrated great potential for use as gain materials because of advantages that include their high photoluminescence quantum yields (PLQYs) and the low-cost and effective chemical manufacturing processes required [7]. The PLQY is more than 85%, and the full width at half maximum (FWHM) of the photoluminescence is approximately 30 nm.…”