Abstract: An object is provision of a method and apparatus for generating ultrashort optical pulses through use of a Raman resonator, which can generate preferentially rotational Raman lines which resonate within the resonator, which can lower the threshold for generation of rotational Raman lines to thereby increase efficiency, and which enables generation of high-order rotational Raman lines to thereby obtain ultrashort optical pulses. An apparatus for generating ultrashort optical pulses by use of a Raman resonator includes a first laser (101); a second laser (102); a first wavemeter (111) for confirming the emitting wavelength of the first laser (101); a second wavemeter (121) for confirming the emitting wavelength of the second laser (102); and a Raman cell (130). These two laser beams are aligned by a beam splitter (113) to become coaxial and are focused by a lens (124) into the Raman cell (130).

Abstract: A dispersing medium containing plural types of particles is let to flow in a flow path formed in a flow cell. The flow cell is irradiated with interfering light to form interference fringes of a pattern of stripes. In another arrangement, light is two-dimensionally scanned at high speed so as to cross a flow in the flow path. The moving particles receive a braking force by the light gradient force whenever they pass through each irradiation light stripe. In that case, greater braking forces act on particles having larger sizes (or larger refractive indices) than on particles having smaller sizes (or smaller refractive indices). Accordingly, the particles receiving smaller braking forces pass through the irradiated position more rapidly, so that particles can be separated to flow in the order from the particles receiving smaller braking forces to the particles receiving greater braking forces.

Abstract: The present invention provides a laser ionization mass spectrometric apparatus comprising a sample introducing portion provided with a pulse valve which forms molecular jet, a pulsed laser beam oscillator, a vacuum ionization chamber or a corresponding portion thereto having a window capable of passing the laser beam radiated from the oscillator, and a mass spectrometer which analyzes the mass of molecules ionized by the laser beam, wherein said pulse laser oscillator has an ability of oscillating ultrashort pulsed laser beam having a peak output of 1 MW or more. The laser ionization mass spectrometric apparatus can use a turbo-molecular vacuum pump to evacuate the above vacuum ionization chamber and the above sample introducing portion can comprise two or more pinhole nozzles.