Laser module

A laser module comprising:

• a laser diode including a plurality of emitters arrayed along a first line, and emitting a laser beam from each one of the plurality of emitters at an emitting surface;
• a first collimator lens disposed facing the emitting surface of the laser diode, and having positive power along a fast axis;
• a beam twister disposed facing the laser beam given off from the first collimator lens, and turning the laser beam by approx. 90 degrees;
• and
• an optical element disposed facing the laser beam given off from the beam twister, and including a plurality of incident surfaces placed in a stepped shape,
• the laser module satisfying conditional expression (1) below for each of the incident surfaces of the optical element:
• x
• 2
• ≤
• (
• f
• w
• 0
• )
• 2
• 
• (
• W
• 2
• 16
• -
• (
• λ
• 
• 
• f
• π
• 
• 
• w
• 0
• )
• 2
• )
• (
• 1
• )
• where, x is a distance from an output surface of the beam twister to the incident surface of the optical element,
• W is a width of the incident surface along the first line,
• λ is a wavelength of the laser beam,
• f is a focal length of the first collimator lens, and
• w0 is a beam diameter of the laser beam along a line perpendicular to the first line, the beam diameter being measured at an output surface of each one of the emitters.