Generation of vacuum ultraviolet radiation by intracavity high-harmonic generation toward state detection of single trapped ions

VUV radiation around 159 nm is obtained toward direct excitation of a single trapped ${}^{115}$In${}^{+}$ ion. An efficient fluoride-based VUV output-coupler is employed for intracavity high-harmonic generation of a Ti:S oscillator. Using this coupler, where we measured its reflectance to be about 90%, an average power reaching $6.4\mu$W is coupled out from a modest fundamental power of 650 mW. When a single comb component out of $1.9\times {10}^5$ teeth is resonant to the atomic transition, hundreds of fluorescence photons per second will be detectable under a realistic condition.