Antiguiding factor of GaN-based laser diodes from UV to green

We measure the antiguiding factor of (Al,In)GaN laser diodes emitting in the violet, blue and green spectral range by combining optical gain-spectroscopy with measurements of the charge-carrier induced refractive index change. A precise determination of the thermal resistance of the laser diodes allows us to keep the temperature of the active region constant during the whole measurement and thus to exclude any thermal effect on the refractive index. For laser diodes emitting in the range from 409 to 511 nm, the antiguiding factor at the laser wavelength is 4.1±0.5.