Approximate Theory of Rectangular Optical Waveguides
... active medium 2. nature of the optical resonator • L decides longitudinal mode separation. W & H decides lateral mode separation • With sufficiently small W & H→only TEM00 lateral mode will exist ( longitudinal modes depends on L ) • Diffraction at the cavity ends →laser beam divergence ( aperture ↓ ...
... active medium 2. nature of the optical resonator • L decides longitudinal mode separation. W & H decides lateral mode separation • With sufficiently small W & H→only TEM00 lateral mode will exist ( longitudinal modes depends on L ) • Diffraction at the cavity ends →laser beam divergence ( aperture ↓ ...
Experiment 3 1 The Michelson Interferometer and the He
... With a population inversion, incident photons of energy E2 – E1 from some other atom can cause stimulated emission from state 2 to state 1. With stimulated emission, the incident photon will trigger ...
... With a population inversion, incident photons of energy E2 – E1 from some other atom can cause stimulated emission from state 2 to state 1. With stimulated emission, the incident photon will trigger ...
Laser Systems for Inverse Compton Scattering Gamma
... at a detector co-located with the source 1 km away from a target consisting of 500 g of 238U [4]. It was estimated that 1014 gammas/s should be produced by the source. This requires the laser to produce the pulse energy of 620 mJ with pulse length 10 ps at a wavelength of 532 nm or the pulse energy ...
... at a detector co-located with the source 1 km away from a target consisting of 500 g of 238U [4]. It was estimated that 1014 gammas/s should be produced by the source. This requires the laser to produce the pulse energy of 620 mJ with pulse length 10 ps at a wavelength of 532 nm or the pulse energy ...
CHAPTER 15. LASER AND FIBER OPTICS The laser is essentially
... laser medium. Pumps can be optical, electrical, chemical, or thermal in nature, so long as they provide energy that can be coupled into the laser medium to excite the atoms and create the required population inversion. Many lasers are named after the type of laser medium used, for example, heliumneo ...
... laser medium. Pumps can be optical, electrical, chemical, or thermal in nature, so long as they provide energy that can be coupled into the laser medium to excite the atoms and create the required population inversion. Many lasers are named after the type of laser medium used, for example, heliumneo ...
11. Electro
... If the photon encounters another atom that has an electron in the same excited state, it can induce the electron to lose its energy in turn (called stimulated emission) The first photon can stimulate atomic emission such that the photon from the second atom has the same frequency and direction a ...
... If the photon encounters another atom that has an electron in the same excited state, it can induce the electron to lose its energy in turn (called stimulated emission) The first photon can stimulate atomic emission such that the photon from the second atom has the same frequency and direction a ...
Operating Principles
... Similarly to an electric circuit, laser oscillation requires a feedback function in addition to a gain which exceeds its loss. A laser beam is oscillated by amplification of stimulated emission and positive feedback with mirrors. ...
... Similarly to an electric circuit, laser oscillation requires a feedback function in addition to a gain which exceeds its loss. A laser beam is oscillated by amplification of stimulated emission and positive feedback with mirrors. ...
Photonic laser thruster
A photonic laser thruster is an amplified laser thruster that generates thrust directly from the laser photon momentum, rather than laser-heating propellant. The concept of single-bounce laser-pushed lightsails that utilize the photon momentum was first developed in the 1960s, however, its conversion of laser power to thrust is highly inefficient, thus has been considered impractical. Over 50 years, there had been numerous theoretical and experimental efforts to increase the conversion efficiency by recycling photons, bouncing them repetitively between two reflective mirrors in an empty optical cavity, without success. In December 2006, Young Bae successfully solved this problem and demonstrated the conversion efficiency enhancement by a factor of 100 and a photon thrust of 35 micronewtons by putting the laser energizing media between the two mirrors as in typical lasers, and the photonic laser thruster was born. In August 2015, the photonic laser thruster was demonstrated to increase the conversion efficiency enhancement by a factor over 1,000 and to achieve a photon thrust of 3.5 millinewtons at Y.K. Bae Corporation. In addition, Propelling, slowing and stopping of a small satellite, 1U CubeSat, in simulated zero-gravity were demonstrated. The photonic laser thruster was initially developed for use in nanometer precision spacecraft formation, for forming ultralarge space telescopes and radars. The photonic laser thruster is currently developed for high-precision and high-speed maneuver of small spacecraft, such as formation flying, orbit adjustments, drag compensation, and rendezvous and docking. The photonic laser thruster can be used for beaming thrust from a conventional heavy resource vehicle to a more expensive & lightweight mission vehicle, similar to tankers in aerial refueling.The practical usage of the photonic laser thruster for main space propulsion would require extremely high laser powers and overcoming technological challenges in achieving the laser power and fabricating the required optics. Photonic laser thrusters have a very high specific impulse, and can permit spacecraft reach much higher speeds than with conventional rockets, which are limited by the Tsiolkovsky rocket equation. If the photonic laser thruster is scalable for the use in such main space propulsion, multiple photonic laser thrusters can be used to construct a 'photonic railway' that has been proposed as a potential permanent transport infrastructure for interplanetary or interstellar commutes, allowing the transport craft themselves to carry very little fuel.