Passive Thermal Mount for One-Tab C-Mount Diode Lasers

  • Passive Heat Sink and Mount for One-Tab C-Mount Diode Lasers
  • Provides up to 2 W of Heat Dissipation
  • Integrated Thermistor for Accurate Temperature Tracking
  • 8-32 (M4) Taps for Post Mounting


LDCM1 with Mounted One-Tab C-Mount Laser (Not Included)

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  • Compatible with One-Tab C-Mount Laser Diodes
  • Provides up to 2 W of Heat Dissipation
  • Post-Mountable Design

Thorlabs’ LDCM1 Passive Thermal Mount provides a passive heat sink and mount that facilitates quick installation and removal for one-tab C-Mount lasers. A 5/64” (2 mm) hex mounting cap screw secures the laser against the bare aluminum mounting surface. This surface ensures thermal contact between the laser and heat sink. It also provides electrical contact for the C-Mount laser's cathode (black lead). A pair of clamping fingers holds the tab of the one-tab C-Mount laser providing electrical contact for the anode (red lead). The LDCM1(/M) is compatible with single-tab laser configurations where the tab is the anode lead (+); please see the diagrams below.

The compact [0.75” × 0.75” × 0.80” (19 mm x 19 mm x 20 mm, L × W × H)], finned aluminum block provides up to 2 W of passive thermal dissipation without thermal grease or tape. At ambient temperatures of 20 °C, this passive regulation will hold the laser under 50 °C. A TH10K thermistor (see specifications in the table to the right) is integrated into the mount close to the laser for accurate temperature monitoring (see image to the right). An 8-32 (M4) threaded hole in the bottom of the mount allows for post mounting.

The passive heat sink does not contain any moving parts (such as a fan) and thus will not impart any vibrations. It places the lasing height at 0.5" above its post-mounting surface. This mount was designed for low-power laser diodes and is fully compatible with one-tab C-Mount laser diodes. Use of thermal grease is also not recommended for use with a C-Mount laser. Thermal grease tends to "creep" and eventually contaminates the laser facets. No additional material is required for thermal contact; however, if the user chooses materials to improve thermal contact, grease must be avoided and the user should ensure that electrical contact with the mount is not broken.

Supported C-Mount Laser Configuration

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Incompatible C-Mount Laser Configuration

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Thermistor attached to passive heat sink
Click to Enlarge
The thermistor is mounted behind the laser diode with its leads accessible through the labeled hole on the side of the mount.
Integrated TH10K Thermistor Specsa
Temp. Accuracy ±1 °C
Dissipation Constant 1.4 mW/°C
Time Constant 15 s
Operating Range -50 to 150 °C
Temp. Coefficient -4.40 %/°C
  • @ 25 °C. We also offer an Excel file that quickly calculates measured resistance for a given temperature, or alternatively, temperature for a measured resistance.

Posted Comments:
info  (posted 2018-12-15 10:43:07.557)
Pay attention to the polarity of the pins ! The enclosure with these pins is compatible only with the laser diodes offered by Thorlabs. Most of the laser diodes in C-mount case available on the market have ANODE (+) connected to the case, and CATHODE (-) on the tab ! This should be marked in the documentation and available wires (colors) for both versions.
mmcclure  (posted 2019-04-01 11:13:37.0)
Hello, thank you for contacting us! We will update the webpage presentation to include this important information.
mikkel.brydegaard  (posted 2018-07-20 11:01:12.167)
Passive Thermal Mount for One-Tab C-Mount Diode Lasers It should rather be a cage plate plate for 30 mm cage system this mount can only be used on a optical table...
YLohia  (posted 2018-07-20 02:31:47.0)
Hello, thank you for your valuable feedback. I have posted this idea on our internal engineering forum for further consideration. This will require a new design since the dimensions of this cube (~19mm sides) are too small to incorporate a 30mm system.
jstafford  (posted 2016-11-29 19:28:42.187)
The dissipation constant for the LDCM1 appears to be a thermal conductance, but it is very low and does not match the description that indicates that there is essentially a 30C rise (up to50C) when operating at 20C. I am assuming that this at 2W which makes the thermal conductivity something like 66 mW/C What am I missing
tfrisch  (posted 2016-12-06 10:37:13.0)
Hello, thank you for contacting Thorlabs. The Dissipation Constant is specific to the TH10K thermistor. The heat from the laser will be primarily dissipated through the fins of the mount, rather than through that thermistor. We do not specify a Dissipation Constant for the mount as a whole, but it provides up to 2W of heat dissipation as you noted.
kylejarnold  (posted 2013-10-23 17:01:53.433)
Regarding LDCM1 for C-mount diode lasers, a useful feature would be tapped holes for 16mm cage system rods, particularly for positioning a SCP05 (xy stage) with collimating aspheric in the front of the diode laser mount. -Kyle Arnold
cdaly  (posted 2013-10-24 15:17:00.0)
Response from Chris at Thorlabs: Thank you for your feedback. The mount is rather small and there would not be enough room to fit cage rod holes on the front face. We plan to come out with a TEC cooled mount in the future which will surely have cage compatibility, but the LDCM1 can still be mounted in the 30mm cage for the time being using the post adapter CPTR20(/M). The lens could be mounted 30mm equivalent XY translator, CXY1.
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