Round trip time calculator





About this calculator

This calculator computes the round trip time and repetition frequency of a pulsed laser cavity. The cavity can consist of up to four different materials with different group indexes and with either single or double pass through them. A ring cavity is an example of a single-pass cavity while a linear cavity is a double-pass cavity.

First, the physical lengths and group indexes of the materials comprising the cavity are used to calculate the optical path length of a single round trip as follows

OPL=2L1ng1+2L2ng2+L3ng3+L4ng4OPL = 2L_1n_{g1} + 2L_2n_{g2} + L_3n_{g3} + L_4n_{g4}

The round trip time τ\tau is then the optical path length divided by the speed of light in vacuum cc

τ=OPLc\tau = \frac{OPL}{c}

and the repetition frequency is the reciprocal of the round trip time

frep=1τf_{rep} = \frac{1}{\tau}