Light-emitting diodes (LEDs) have had quite an impact on modern technology, powering everything from smartphone displays to large-scale lighting. Yet, there is one thing LEDs cannot do easily and that's produce coherent light states. LED emission is broad and uncoordinated, as the light waves are not aligned in phase, so they spread in many directions and cannot form a sharp, focused beam. Lasers, in contrast, emit narrow and coherent beams but require a process called population inversion, which is energy demanding and harder to integrate into compact devices.

Researchers are turning to optically pumped perovskite LEDS as a promising way to produce coherent light without population inversion. Their operation depends on optically pumped polaritons, hybrid particles formed when light and matter strongly couple inside a microcavity. Optically pumped polaritons enable perovskite LEDs to combine the efficiency of traditional LEDs with the coherence of lasers, an effect that researchers examine using microspectrophotometry.

The ability to control light at the quantum level has long been constrained by the need for cryogenic temperatures and complex material systems. Because room temperatures cannot sustain quantum coherence, researchers have traditionally relied on cryogenic set ups and complex machines, despite their cost and size, to stabilize light-matter interactions. Room temperature polaritons offer an interesting alternative. Enabled through 2D perovskite systems, these polaritons form under ambient conditions, where the materials’ unique optical and structural properties naturally support strong coupling. As a result, room temperature 2D perovskite systems are paving the way to accessible, high-performance quantum photonic technologies

Perovskite materials are highly valued for their efficient, tunable light emission, a property that opens up new possibilities in displays, sensors, lasers, and other photonic technologies. But producing light is only one aspect of what modern photonic devices require. Equally as important is the ability to control how that light behaves, including its wavelength, direction, and coherence, which directly impacts device performance and functionality. Optical quasi-bound-states-in-the-continuum (quasi-BICs) provide a precise mechanism for controlling perovskite emissions using carefully engineered photonic structures. By aligning these structures with the emission characteristics of perovskites, researchers can enhance spectral control, improve efficiency, and enable new device functionalities.

Across crime scenes and forensic laboratories, some of the most decisive evidence arrives in the form of almost invisible threads. Microfibers, released from everyday textiles like clothing or furnishings, can transfer during fleeting contact and linger undetected. Their ability to connect people, places, and objects has made them a cornerstone of forensic trace analysis. But when two fibers appear virtually identical under a microscope, how do investigators tell them apart? The answer lies in a technique that examines the molecular traces left behind by light itself: UV-Vis-NIR microspectroscopy.