Optics / Photonics 101

Photometer - Definition and References

Photometer is an instrument for measuring the light intensity or optical properties of optical sources or detectors. It operates more like a transducer which converts electric current into mechanical signal.

29 May 2014

Population Inversion - Definition and References

Population inversion is a condition of the laser medium where a system consisting of a group of molecules or atoms exists in a higher excited state with more quantum systems than that of the lower energy state of a laser transition.

29 May 2014

Radiant Flux - Explanation and References

Radiant flux is the energy per unit time that is radiated from an optical source, expressed in terms of Watts.

29 May 2014

Brewster Window - Definition and Applications

A Brewster window is an uncoated substrate that is positioned at Brewster’s angle within a laser, instead of external mirrors. This substrate acts as a polarizer such that the p-polarized light enters and exits the window without reflection losses, while the s-polarized light is reflected.

15 May 2014

An Introduction Doppler Cooling

Doppler cooling is the laser based cooling of small particles, such as ions and atoms, which are trapped during the cooling process. It also involves the spontaneous emission of photons, which generate velocity-dependent light forces through the Doppler effect.

15 May 2014

Giles Parameters - Definition and Equation

Giles parameters are used to design fiber amplifiers that are made of rare-earth-doped fibers.

15 May 2014

Free-Electron Laser - Definition and Applications

A free-electron laser is a kind of laser that employs a beam of high-speed, relativistic electrons moving freely with an optical field via a magnetic structure.

15 May 2014

Harmonic Mode-Locking - Definition

Harmonic mode-locking is a method of achieving high pulse repetition rates in an actively mode-locked laser. This method is carried out in the laser resonator with a constant temporal spacing where multiple ultra-short pulses are circulated.

15 May 2014

Hermite-Gaussian Modes - Explanation and Equation

Propagation of light in a free space or a homogenous optical medium changes the intensity profile of light. In certain electric field amplitude distributions, the shape of the amplitude profile remains constant.

15 May 2014

Moiré Pattern - Description and Applications

Moiré patterns occur when materials are overlapped with repetitive lines. It is a naturally occurring interference pattern created by overlaying similar but slightly offset templates.

15 May 2014