Multiple-prism grating laser oscillator

Multiple-prism grating laser oscillators, or MPG laser oscillators, use multiple-prism beam expansion to illuminate a diffraction grating mounted either in Littrow configuration or grazing-incidence configuration. Originally, these narrow-linewidth tunable dispersive oscillators were introduced as multiple-prism Littrow (MPL) grating oscillators, or hybrid multiple-prism near-grazing-incidence (HMPGI) grating cavities, in organic dye lasers. However, these designs were quickly adopted for other types of lasers such as gas lasers, diode lasers, and more recently fiber lasers. Multiple-prism grating laser oscillators can be excited either electrically, as in the case of gas lasers and semiconductor lasers, or optically, as in the case of crystalline lasers and organic dye lasers. In the case of optical excitation it is often necessary to match the polarization of the excitation laser to the polarization preference of the multiple-prism grating oscillator. This can be done using a polarization rotator thus improving the laser conversion efficiency. The multiple-prism dispersion theory is applied to design these beam expanders either in additive configuration, thus adding or subtracting their dispersion to the dispersion of the grating, or in compensating configuration (yielding zero dispersion at a design wavelength) thus allowing the diffraction grating to control the tuning characteristics of the laser cavity. Under those conditions, that is, zero dispersion from the multiple-prism beam expander, the single-pass laser linewidth is given by where is the beam divergence and M is the beam magnification provided by the beam expander that multiplies the angular dispersion provided by the diffraction grating. In the case of multiple-prism beam expanders this factor can be as high as 100–200. When the dispersion of the multiple-prism expander is not equal to zero, then the single-pass linewidth is given by where the first differential refers to the angular dispersion from the grating and the second differential refers to the overall dispersion from the multiple-prism beam expander.

Persistent enhancement of exciton diffusivity in CsPbBr3 nanocrystal solids

Seryio Saris

In semiconductors, exciton or charge carrier diffusivity is typically described as an inherent material property. Here, we show that the transport of excitons among CsPbBr3 perovskite nanocrystals (NCs) depends markedly on how recently those NCs were occup ...

Amer Assoc Advancement Science2024

Single-frequency violet and blue laser emission from AlGaInN photonic integrated circuit chips

Tobias Kippenberg, Anat Siddharth

Chip-based, single-frequency and low phase-noise integrated photonic laser diodes emitting in the violet (412 nm) and blue (461 nm) regime are demonstrated. The GaN-based edge-emitting laser diodes were coupled to high-quality on-chip micro-resonators for ...

Optica Publishing Group2023

Accurate time zero determination in an ultrafast transmission electron microscope without energy filter

Marcel Drabbels, Ulrich Lorenz, Pavel Olshin, Jonathan Mark Voss

In this manuscript, we describe a simple and accurate method for finding the temporal overlap of the laser pump and electron probe pulse in ultrafast TEM. Our approach is based on the observation that the outline of a nanoparticle blurs at time zero, a phe ...

2022