We have developed a technique for modulating a xenon (Xe) lamp that is usually driven by a direct-current (dc) mode. The lamp current is sinusoidally modulated using a metal-oxide-semiconductor field-effective-transistor (MOSFET), which is connected in series to the Xe lamp.To operate in a high frequency region, an LC filter is attached on the anode side of the Xe lamp.The degree of modulation was 90% at a frequency 1 kHz and was 25% at a frequency 100 kHz, respectively. In combination with a lock-in amplifier, fluorescence measurement under the dc background light was carried out to demonstrate the performance of the modulated Xe lamp.