Maculopathy following exposure to visible and infrared radiation from a laser pointer: a clinical case study.

Purpose: Laser pointer devices have become increasingly available in recent years, and their misuse has caused a number of ocular injuries. Online distribution channels permit trade in devices which may not conform to international standards in terms of their output power and spectral content. We present a case study of ocular injury caused by one such device.

Sub-300-femtosecond operation from a MIXSEL.

Peak power scaling of semiconductor disk lasers is important for many applications, but their complex pulse formation mechanism requires a rigorous pulse characterization to confirm stable fundamental modelocking. Here we fully confirm sub-300-fs operation of Modelocked Integrated eXternal-cavity Surface Emitting Lasers (MIXSELs) with record high peak power at gigahertz pulse repetition rates. A strain-compensated InGaAs quantum well gain section enables an emission wavelength in the range of Yb-doped amplifiers at ≈1030 nm.

Dual-comb modelocked laser.

In this paper we present the first semiconductor disk laser (SDL) emitting simultaneously two collinearly overlapping cross-polarized gigahertz modelocked pulse trains with different pulse repetition rates. Using only a simple photo detector and a microwave spectrum analyzer directly down-converts the frequency comb difference from the optical to the microwave frequency domain. With this setup, the relative carrier-envelope-offset (CEO) frequency can be accessed directly without an f-to2f interferometer.

Gigahertz self-referenceable frequency comb from a semiconductor disk laser.

We present a 1.75-GHz self-referenceable frequency comb from a vertical external-cavity surface-emitting laser (VECSEL) passively modelocked with a semiconductor saturable absorber mirror (SESAM). The VECSEL delivers 231-fs pulses with an average power of 100 mW and is optimized for stable and reliable operation.

Pulse repetition rate scaling from 5 to 100 GHz with a high-power semiconductor disk laser.

The high-power semiconductor laser studied here is a modelocked integrated external-cavity surface emitting laser (MIXSEL), which combines the gain of vertical-external-cavity surface-emitting lasers (VECSELs) with the saturable absorber of a semiconductor saturable absorber mirror (SESAM) in a single semiconductor layer stack. The MIXSEL concept allows for stable and self-starting fundamental passive modelocking in a simple straight cavity and the average power scaling is based on the semiconductor disk laser concept. Previously record-high average output power from an optically pumped MIXSEL was demonstrated, however the long pulse duration of 17 ps prevented higher pulse repetition rates and many interesting applications such as supercontinuum generation and broadband frequency comb generation.

Femtosecond pulses from a modelocked integrated external-cavity surface emitting laser (MIXSEL).

Novel surface-emitting optically pumped semiconductor lasers have demonstrated >1 W modelocked and >100 W continuous wave (cw) average output power. The modelocked integrated external-cavity surface emitting laser (MIXSEL) combines the gain of vertical-external-cavity surface-emitting lasers (VECSELs) with the saturable absorber of a semiconductor saturable absorber mirror (SESAM) in one single semiconductor structure. This unique concept allows for stable and self-starting passive modelocking in a simple straight cavity.

VECSEL gain characterization.

We present the first full gain characterization of two vertical external cavity surface emitting laser (VECSEL) gain chips with similar designs operating in the 960-nm wavelength regime. We optically pump the structures with continuous-wave (cw) 808-nm radiation and measure the nonlinear reflectivity for 130-fs and 1.4-ps probe pulses as function of probe pulse fluence, pump power, and heat sink temperature.

Femtosecond VECSEL with tunable multi-gigahertz repetition rate.

We present a femtosecond vertical external cavity surface emitting laser (VECSEL) that is continuously tunable in repetition rate from 6.5 GHz up to 11.3 GHz.