Device for forming visible image in air

A device for forming a visible image comprising:

• a pulse laser source which irradiates a pulse laser beam with a pulse width of 50 ns or less;
• a visible-region laser source which is coaxial with the pulse laser beam and irradiates a visible-region laser beam;
• a scanning device which coaxially scans each of the pulse laser beam and visible-region laser beam;
• a condensing optical system which condenses the pulse laser beam at a drawing scheduled point in air or water so as to generate a fluctuation in a refractive index by heating a gas or liquid at the drawing scheduled point;
• and
• a controlling device which controls oscillation timing of the pulse laser source and scans timing of the scanning device so as to generate the fluctuation in the refractive index at the drawing scheduled point in a time series and draw a visible image by generating a residual image phenomenon of the scattered luminescent spots through irradiation of the visible-region laser beam in the time series,
• wherein the condensing optical system comprises a convex mirror provided to reflect the invisible-region laser beam as a scattered light and a concave mirror provide to condense the pulse laser beam reflected by the convex mirror at each of the drawing scheduled points, and the concave mirror has a transparent window coaxially formed through which the pulse laser beam is transmitted.

A device for forming a visible image comprising:

• a pulse laser source which irradiates a pulse laser beam with a pulse width of 50 ns or less in visible-region;
• a scanning device which scans the pulse laser beam;
• a condensing optical system which condenses the pulse laser beam at a drawing scheduled point in air or water so as to generate a fluctuation in a refractive index by heating a gas or liquid at the drawing scheduled point;
• and
• a controlling device which controls oscillation timing of the pulse laser source and scans timing of the scanning device so as to generate the fluctuation in the refractive index at the drawing scheduled point in a time series and draw a visible image by generating a residual image phenomenon of scattered luminescent spots through irradiation of the visible-region laser beam in the time series.