Class IdealEtalon

Inheritance Relationships

Base Type

Class Documentation

class IdealEtalon : public CalibrationSource

Implements the spectral density of an ideal fabry-perot etalon.

An ideal Fabry-Perot etalon has a transmission function that only depends on the distance of the mirrors, the angle of incidence, the reflectivity of the mirrors and the refractive index of the medium between the mirrors.

\[ s(\lambda) = \frac{1}{cF sin(\frac{\delta} {2})^2} \]

(

It produces a comb-like spectrum that is has equidistant peaks in frequency.

See

IdealEtalon::T())

Todo:

implement FSR(), F() and other static functions.

Public Functions

IdealEtalon(double d, double n, double theta, double R, double I)

Constructor.

Parameters

  • d – mirror distance in mm

  • n – refractive index of the medium between mirrors

  • theta – angle of incidence

  • R – reflectivity of the mirrors

  • I – flux density [microWatts]/[micrometer] of the underlying light source

Public Static Functions

static double coefficient_of_finesse(double R)

Calculates the coefficient of Finesse.

\[ cF = \frac{4 R}{(1-R)^2} \]

Warning

This is not what is typically called the finesse of an etalon, but the coefficient of finesse.

Parameters

R – mirror reflectivity

Returns

coefficienct of finesse

static double T(double wl, double theta, double d, double n, double cF)

Transmission function of an ideal etalon.

\[ T(\lambda) = \frac{1}{cF sin(\frac{\delta} {2})^2} \]
, where
\[ \delta \left( \frac{2\pi}{\lambda} \right) 2nlcos(\Theta) \]
, is the phase difference and \( F \) is the coefficient of finesse:
\[ cF = \frac{4R}{(1-R)^2} \]

See

IdealEtalon::coefficient_of_finesse

Parameters

  • wl – wavelength [micron]

  • theta – angle of incidence [rad]

  • d – mirror distance [mm]

  • n – refractive index

  • cF – coefficient of finesse

Returns

transmission at given wavelength

Protected Functions

virtual double get_spectral_density(double wavelength)

Spectral density at given wavelegnth.

Parameters

wavelength – wavelength [micron]

Returns

Spectral density at given wavelength