Photonics Dictionary: Q

The transform defining that, if a reference beam is a divergent spherical wavefront, then the reconstructed image will be the equivalent of the near-field diffraction pattern of the object. Also...

Conceptual formulas that characterize both the transmittance functions of lenses and propagation in the Fresnel zone.

Quantitative phase imaging (QPI) is an advanced imaging technique used in microscopy to measure and analyze the optical phase information of transparent specimens. Unlike traditional brightfield...

The term quantum refers to the fundamental unit or discrete amount of a physical quantity involved in interactions at the atomic and subatomic scales. It originates from quantum theory, a branch of...

Quantum key distribution (QKD) is a method of secure communication that utilizes principles from quantum mechanics to establish a shared secret key between two parties, typically referred to as Alice...

Quantum sensing refers to a class of sensing technologies that leverage principles from quantum mechanics to enhance the precision and sensitivity of measurements. Traditional sensors operate based...

A quantum well is a structure in quantum mechanics that confines particles, such as electrons or holes, in one spatial dimension. This confinement leads to quantized energy levels, creating a...

A plate made of a double-refracting crystal having such a density that a phase difference of one-quarter cycle is formed between the ordinary and extraordinary elements of light passing through.

A qubit, short for quantum bit, is the fundamental unit of information in quantum computing and quantum information processing. Unlike classical bits, which can exist in one of two states (0 or 1),...