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The frequency is the threshold frequency for the given material. Above that frequency, the maximum kinetic energy of the photoelectrons as well as the stopping voltage in the experiment V o = h e ( ν − ν o ) {\textstyle V_{o}={\frac {h}{e}}\left(\nu -\nu _{o}\right)} rise linearly with the frequency, and have no dependence on the number of ...
The threshold voltage, commonly abbreviated as V th or V GS(th), of a field-effect transistor (FET) is the minimum gate-to-source voltage (V GS) that is needed to create a conducting path between the source and drain terminals. It is an important scaling factor to maintain power efficiency.
A special case is the degenerate OPO, when the output frequency is one-half the pump frequency, = = /, which can result in half-harmonic generation when signal and idler have the same polarization. The first optical parametric oscillator was demonstrated by Joseph A. Giordmaine and Robert C. Miller in 1965, [ 2 ] five years after the invention ...
A frequency comb or spectral comb is a spectrum made of discrete and regularly spaced spectral lines.In optics, a frequency comb can be generated by certain laser sources.. A number of mechanisms exist for obtaining an optical frequency comb, including periodic modulation (in amplitude and/or phase) of a continuous-wave laser, four-wave mixing in nonlinear media, or stabilization of the pulse ...
It is also occasionally referred to as temporal frequency for clarity and to distinguish it from spatial frequency. Ordinary frequency is related to angular frequency (symbol ω, with SI unit radian per second) by a factor of 2 π. The period (symbol T) is the interval of time between events, so the period is the reciprocal of the frequency: T ...
Difference-frequency generation (DFG), generation of light with a frequency that is the difference between two other frequencies. Optical parametric amplification (OPA), amplification of a signal input in the presence of a higher-frequency pump wave, at the same time generating an idler wave (can be considered as DFG).
The SI unit of spatial frequency is the reciprocal metre (m −1), [1] although cycles per meter (c/m) is also common. In image-processing applications, spatial frequency is often expressed in units of cycles per millimeter (c/mm) or also line pairs per millimeter (LP/mm). In wave propagation, the spatial frequency is also known as wavenumber.
The cutoff frequency is the critical frequency between propagation and attenuation, which corresponds to the frequency at which the longitudinal wavenumber is zero. It is given by ω c = c ( n π a ) 2 + ( m π b ) 2 {\displaystyle \omega _{c}=c{\sqrt {\left({\frac {n\pi }{a}}\right)^{2}+\left({\frac {m\pi }{b}}\right)^{2}}}} The wave equations ...