Increased Sensitivity of Higher-Order Laser Beams to Mode Mismatches

This manuscript derives explicit factors linking mode-mismatch-induced power losses, in Hermite-Gauss optical modes to the losses of the fundamental spatial mode. Higher order modes are found to be more sensitive to beam parameter mismatches. This is particularly relevant for gravitational-wave detectors, where lasers employing higher-order optical modes have been proposed to mitigate thermal noise and quantum-enhanced detectors are very susceptible to losses. This work should inform mode matching and squeezing requirements for $\mathit{\text{Advanced+}}$ and $\mathit{\text{Third}}\mathit{\text{Generation}}$ detectors.