Ultrafast optical Kerr gate at 1 GHz repetition rate by focusing on bismuth borosilicate (BBS) glass

The optical Kerr gating (OKG) technique is promising for its high efficiency, broad spectral range, and sub-picosecond temporal resolution, without phase-matching requirements. Traditionally, however, OKG setups have been limited by the need for millijoule-level pulse energies from complex amplifier systems, making them difficult to apply to single emitters. Here, we present an ultrafast OKG scheme using bismuth borosilicate (BBS) glass that operates at a 1 GHz repetition rate under focusing with low pulse energies (<1 nJ) and a gate-pulse peak intensity of ∼ 1.20 GW/cm2. Achieving 175 fs temporal resolution, this microscopy-compatible platform leverages the high nonlinearity and sub-picosecond temporal resolution of BBS glass to enable investigation of ultrafast processes in single quantum emitters.