Laser module

A laser module comprising:

• a quantum cascade laser element;
• a diffraction grating unit including a movable diffraction grating that constitutes an external resonator for the quantum cascade laser element;
• a first lens holder disposed on a side opposite to a side where the movable diffraction grating is positioned with respect to the quantum cascade laser element and configured to hold a first lens for allowing a first output light from the quantum cascade laser element to pass through;
• a second lens holder disposed between the quantum cascade laser element and the movable diffraction grating and configured to hold a second lens for allowing a second output light from the quantum cascade laser element and a light returning from the movable diffraction grating to the quantum cascade laser element to pass through;
• a mount member that mounts the quantum cascade laser element, the diffraction grating unit, the first lens holder, and the second lens holder;
• and
• a housing that includes a bottom wall on which the mount member is placed and accommodates the quantum cascade laser element, the diffraction grating unit, the first lens holder, the second lens holder, and the mount member;
• wherein the mount member includes a first mounting section, a second mounting section, a third mounting section, and a fourth mounting section sequentially arranged from the first lens holder side to the diffraction grating unit side along a first direction in which the first lens holder and the second lens holder face each other;
• wherein the first mounting section includes:
• a first mounting surface on which the first lens holder is mounted;
• and
• a first surface facing the bottom wall on an opposite side of the first mounting surface,
• wherein the second mounting section includes:
• a second mounting surface on which the quantum cascade laser element and a temperature sensor are mounted;
• and
• a second surface facing the bottom wall on an opposite side of the second mounting surface,
• wherein the third mounting section includes:
• a third mounting surface on which the second lens holder is mounted;
• and
• a third surface facing the bottom wall on an opposite side of the third mounting surface,
• wherein the fourth mounting section includes:
• a fourth mounting surface on which the diffraction grating unit is mounted, and
• wherein at least the second surface is fixed to the bottom wall via a medium having a higher thermal conductivity than air and filled between the second surface and the bottom wall.