Pound Drever Hall Quantum Shot Noise

PDH quantum shot noise is a fundamental noise floor for laser measurements.

The equation for quantum PDH shot noise is

\[ S(f) = 2 \hbar \omega_0 P_0 \left[J_0(\Gamma)^2 (1-\eta) +3 J_1(\Gamma)^2\right] \]

where $\hbar$ is the reduced Planck's constant, $\omega_0$ is the carrier laser frequency, $P_0$ is the power incident on the photodetector, $J_0$ and $J_1$ are Bessel functions of the first kind, $\Gamma$ is the modulation depth, and $\eta$ is your Fabry-Perot cavity visibility from the reflection port.

The shot noise PSD $S(f)$ is in units of power $\left[ \dfrac{ \text{W}^2 }{ \text{Hz} } \right]$

Pound Drever Hall Quantum Shot Noise Calculator

Type a values to the Incident Power, Modulation Depth, and Cavity Visibility fields to get a PDH Quantum Shot Noise estimate.

Incident Power on the Photodiode $P_0$: mW

Laser Wavelength $\lambda = \frac{2 \pi c}{\omega_0}$: nm

Modulation Depth $\Gamma$:

Cavity Visibility $\eta$: (between 0 and 1, visibility from the reflection port)

Laser Frequency $\nu_0 = \frac{\omega_0}{2 \pi}$: THz

Bessel Function $J_0(\Gamma)$:

Bessel Function $J_1(\Gamma)$:

Shot Noise $S(f)$: $ \dfrac{\text{W}^2}{\text{Hz}} $

Created by Craig Cahillane, 2017 November 26