Photocatalytic-ready supraparticle lasers

A photocatalytic-ready supraparticle laser consisting of a micron-scale CdS x Se 1-x /ZnS quantum dot assembly and a titania shell is demonstrated. Such multifunctional supraparticles could find use in future defence, environment, energy and medical technologies

Alloyed-core colloidal quantum dot DFB laser with encapsulated gain region

A CdSxSe1−x/ZnS colloidal quantum dot distributed-feedback laser operating in the nanosecond-regime with a threshold below 3 kW/cm2 is reported. The laser emits vertically up to 40 nJ at 600 nm with an efficiency of 1.2%

Diode-pumped, mechanically-flexible polymer DFB laser encapsulated by glass membranes

A diode-pumped, mechanically-flexible organic distributed-feedback laser that is fully encapsulated with ultra-thin glass is reported. The organic laser is excited by 450nm laser diode and emits at 537 nm with an oscillation threshold of 290 W/cm2. The encapsulation format of the device results in a photostability that is improved by two orders of magnitude compared to a non-encapsulated reference device while maintaining mechanical flexibility thanks to an overall device thickness below 105 μm. The laser is also wavelength-tunable between 535 nm and 545 nm by bending the ultra-thin glass structure

RGB and white-emitting organic lasers on flexible glass

Two formats of multiwavelength red, green and blue (RGB) laser on mechanically-flexible glass are demonstrated. In both cases, three all-organic, vertically-emitting distributed feedback (DFB) lasers are assembled onto a common ultra-thin glass membrane substrate and fully encapsulated by a thin polymer overlayer and an additional 50µm-thick glass membrane in order to improve the performance. The first device format has the three DFB lasers sitting next to each other on the glass substrate. The DFB lasers are simultaneously excited by a single overlapping optical pump, emitting spatially separated red, green and blue laser output with individual thresholds of, respectively, 28 µJ/cm2, 11 µJ/cm2 and 32 µJ/cm2 (for 5 ns pump pulses). The second device format has the three DFB lasers, respectively the red, green and blue laser, vertically stacked onto the flexible glass. This device format emits a white laser output for an optical pump fluence above 42 µJ/cm2

InGaN micro-LEDs integrated onto an ultra-thin, colloidal quantum dot functionalized glass platform

We demonstrate an integrated color-converting device by transfer printing blue-emitting micro-sized InGaN LEDs onto an ultra-thin glass platform functionally enhanced with colloidal quantum dots. Color conversion and waveguiding properties of the structure are presented

Hybrid GaN microLED platform for fluorescence sensing

A hybrid GaN μLED platform developed for wearable illumination is adapted here for fluorescence sensing. Proof-of-principle detection of colloidal quantum dots down to 80 pM using a mobile phone camera is demonstrate

Amplifying organic semiconductor waveguide based nanocrystal sensor

We demonstrate an optical sensor that consists of an amplifying organic semiconductor waveguide with a protective polymer cladding for photostability. Sensing is achieved by evanescence of the guided amplified spontaneous emission (ASE) combining high signal levels at detection with simplicity of implementation. We show correlations between the presence and concentration of colloidal semiconductor nanoparticles on the cladding surface and changes in both the ASE threshold and the optical gain

Amplifying organic semiconductor waveguide based nanocrystal sensor

We demonstrate an optical sensor that consists of an amplifying organic semiconductor waveguide with a protective polymer cladding for photostability. Sensing is achieved by evanescence of the guided amplified spontaneous emission (ASE) combining high signal levels at detection with simplicity of implementation. We show correlations between the presence and concentration of colloidal semiconductor nanoparticles on the cladding surface and changes in both the ASE threshold and the optical gain

Organic semiconductor laser platform for the detection of DNA by AgNP plasmonic enhancement

Organic semiconductor lasers are a sensitive biosensing platform that respond to specific biomolecule binding events. So far, such biosensors have utilized protein-based interactions for surface functionalization but a nucleic acid–based strategy would considerably widen their utility as a general biodiagnostic platform. This manuscript reports two important advances for DNA-based sensing using an organic semiconductor (OS) distributed feedback (DFB) laser. First, the immobilization of alkyne-tagged 12/18-mer oligodeoxyribonucleotide (ODN) probes by Cu-catalyzed azide alkyne cycloaddition (CuAAC) or “click-chemistry” onto an 80 nm thick OS laser film modified with an azide-presenting polyelectrolyte monolayer is presented. Second, sequence-selective binding to these immobilized probes with complementary ODN-functionalized silver nanoparticles, is detected. As binding occurs, the nanoparticles increase the optical losses of the laser mode through plasmonic scattering and absorption, and this causes a rise in the threshold pump energy required for laser action that is proportional to the analyte concentration. By monitoring this threshold, detection of the complementary ODN target down to 11.5 pM is achieved. This complementary binding on the laser surface is independently confirmed through surface-enhanced Raman spectroscopy (SERS)

MQW nanomembrane assemblies for visible light communications

We report color-conversion of InGaN LEDs and lasers using an AlInGaP multi-quantum-well nanomembrane. In particular, we demonstrate free-space OOK data transmission at 180 Mb/s from a laser diode blue-to-red converted by a heterogeneous nanomembrane/sapphire lens assembly