Ionize hydrogen gas with 405 nm laser?

[Sven Andersson]

Does laser light from a powerful violet laser with wavelength 405 nm create significant ionization in a gas (Hydrogen or Helium) if shone through it? Will there be a streak of ionized molecules/atoms in the beam, so to speak? Can that ionization be detected easily with a voltmeter? How effective is ionization with 405 nm laser light compared to other methods of ionization?

 

[blue_leaf77]

Single photon ionization may not be possible, but multiphoton ionization might do the job. The rate of multiphoton ionization scales with intensity, so you will need to focus your laser.