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We present a novel, to the best of knowledge, time-resolved, optical pump/NIR supercontinuum probe spectrometer suitable for oscillators. A NIR supercontinuum probe spectrum (850–1250 nm) is generated in a photonic crystal fiber, dispersed across a digital micromirror device (DMD), and then raster scanned into a single element detector at a 5 Hz rate. Dual modulation of pump and probe beams at disparate frequencies permits simultaneous measurement of both the bare reflectanceRand its photoinduced change ΔRthrough lock-in detection, allowing for continuously self-normalized measurement of ΔR/R. Example data are presented on a germanium wafer sample that demonstrate for signals of order ΔR/R ∼ 10⁻³, a 2.87 nm spectral resolution and$\lesssim <\#comment/>400$ fs temporal resolution pre-recompression, and comparable sensitivity to standard time-resolved, amplifier-based pump–probe techniques.

We report on an ultralow probe-power transient grating apparatus with probing based on a laser diode pulser, a digital delay generator, and a data acquisition card. The electronic triggering of the diode pulser permits stroboscopic measurement of arbitrarily slow laser-induced dynamics using pulses of probe light with average power$\sim <\#comment/>5\mathrm{n}\mathrm{W}$, significantly lower than what is currently used by continuous wave measurement. The proposed method also allows for flexibility in selection of the probe wavelength limited only by availability of low threshold current laser diodes. Examples of impulsive stimulated thermal scattering measurements are presented on liquid isopropanol, single crystal solid${\mathrm{C}\mathrm{r}\mathrm{C}\mathrm{l}}_3$, and a thin film of Cu vapor deposited on a Si substrate, demonstrating the flexibility of the technique.