Coherent soft X-ray high-order harmonics using tight-focusing laser pulses in the gas mixture.
We experimentally study the harmonics from a Xe-He gas mixture using tight-focusing femtosecond laser pulses. The spectrum in the mixed gases exhibits an extended cutoff region from the harmonic H21 to H27. The potential explanation is that the harmonics photons from Xe contribute the electrons of He atoms to transmit into the excited-state. Therefore, the harmonics are emitted from He atoms easily. Furthermore, we show that there are the suppressed harmonics H15 and H17 in the mixed gases. The underlying mechanism is the destructive interference between harmonics generated from different atoms. Our results indicate that HHG from Xe-He gas mixture is an efficient method of obtaining the coherent soft X-ray source.
National Key Laboratory of Science and Technology on Tunable Laser, Institute of Opto-Electronics, Harbin Institute of Technology, Harbin, Heilongjiang, China.
Faming
F
Lu
National Key Laboratory of Science and Technology on Tunable Laser, Institute of Opto-Electronics, Harbin Institute of Technology, Harbin, Heilongjiang, China.
Yuanqin
Y
Xia
National Key Laboratory of Science and Technology on Tunable Laser, Institute of Opto-Electronics, Harbin Institute of Technology, Harbin, Heilongjiang, China.
Sheng
S
Zhang
National Key Laboratory of Science and Technology on Tunable Laser, Institute of Opto-Electronics, Harbin Institute of Technology, Harbin, Heilongjiang, China.
Deying
D
Chen
National Key Laboratory of Science and Technology on Tunable Laser, Institute of Opto-Electronics, Harbin Institute of Technology, Harbin, Heilongjiang, China.
Yang
Y
Zhao
National Key Laboratory of Science and Technology on Tunable Laser, Institute of Opto-Electronics, Harbin Institute of Technology, Harbin, Heilongjiang, China.
Bin
B
Liu
D000162:Acoustics; D004867:Equipment Design; D005740:Gases / Q000032:analysis / Q000737:chemistry*; D007834:Lasers; D013057:Spectrum Analysis / Q000295:instrumentation* / Q000379:methods; D014965:X-Rays
D005740:Gases
Femtosecond laser pulses; gas mixture; high harmonic generation; soft X-ray