Microscope Slide Power Meter


Microscope Slide Power Meter Sensor Head

  • Measure Power at the Sample
  • Large-Area Diode to Collect Light from High NA Objectives
  • 20mm x 20mm Indentation Above Detector Accepts Immersion Medium
  • Detects Light Between 350 nm and 1100 nm


  • Compatible with Standard Upright and Inverted Microscopes
  • Wavelength Range: 350 nm to 1100 nm
  • Sensitive to Optical Powers from 10 nW to 150 mW
  • Silicon Photodiode with Large 18 mm x 18 mm Active Area
  • Sensor Housing Dimensions: 76.0 mm x 25.2 x 5.0 mm
  • Novel Optical Design to Accomodate High NA Objectives
  • Information Stored in Connector:
    • Sensor Data
    • NIST- and PTB-Traceable Calibration Data
  • Post Mountable via 8-32 (M4) Tap

The S170C Microscope Slide Power Sensor Head is a silicon photodiode sensor designed to measure optical power at the sample in microscopy setups. The 76.0 mm x 25.2 x 5.0 mm sensor head has the same footprint as a standard microscope slide and is compatible with most standard upright and inverted microscopes. The large-area silicon photodiode, with an active area of 18 mm x 18 mm, can detect wavelengths between 350 nm and 1100 nm at optical powers between 10 nW and 150 mW.

The sensor is contained within a sealed housing, behind a neutral density (ND) filter with OD 1.5. The sensor head features a novel optical design that supports power measurements for objectives with NAs up to 1.45. 

A 20 mm x 20 mm indentation around the surface of the ND filter is sized to accept standard microscope cover slip. An immersion medium (water, glycerol, oil, etc.) may be placed in this well directly over the ND filter, or a cover slip may be inserted first to simplify clean up. The cover slip and the top surface of the housing are easy to clean using the same procedures as for focusing optics. Cleaning instructions can be found on the Specs tab.

The bottom of the sensor housing features a laser-engraved grid that marks the sensor active area to aid in aligning and focusing the beam. To use with a standard upright microscope, insert the housing into the beam path so that the engraved side is facing the objective of your microscope. Once the power sensor is centered under the objective, turn the slide over so that the detector is facing the beam in order to take a power measurement. For inverted microscopes, place the S170C in your slide holder with the sensor facing the objective and turn on the transmitted illuminator. Centering the beam on the engraved target will center the sensor in the optical path.

A 1.5 m cable attached to the side of the sensor head leads to a D-sub 9-pin male connector. Sensor specifications and the NIST- and PTB-traceable calibration data are stored in non-volatile memory in the sensor connector and can be read out by the latest generation of Thorlabs power meter consoles.

The S170C power sensor is compatible with the PM100D, PM100A, PM100USB, PM200, and PM320E power meters consoles. The PM100A, PM100D, and PM200 consoles are sold below for convenience. The PM100A power meter console is an analog device that provides all of the basic functions needed to use the S170C. The PM100D digital power meter console features a back-lit LED screen and includes a 1 GB external SD memory card. The PM200 touch screen power meter console can perform the same functions as the PM100A and PM100D with the added feature of storing past power measurements in its 128 GB internal memory. Data may also be saved on a USB flash drive. This function is particularly useful for tracking the consistency of the power at the sample plane over time.


Microscope Slide Power Meter Sensor Head

  • Designed to Measure Optical Power at the Sample Plane
  • Sensor Head has the Same 76.0 mm x 25.2 mm Footprint
    as a Standard Microscope Slide
  • Large 18 mm x 18 mm Sensor Active Area
  • Ideal for Measuring Light from High NA Objectives and Microscope Back Aperture
  • Yearly Recalibration with CAL1 Recalibration Service Recommended


The S170C Microscope Slide Power Meter Head is designed to fit in the microscope slide holders of standard upright and inverted microscopes to measure the power at the sample plane. The sensor head features a 20 mm x 20 mm indent above the ND filter that accepts immersion media.


The back of the slide is engraved with the sensor specifications and a grid for aligning the beam. The photo to the right shows the engraving being used to center the beam on the slide in an upright microscope. To take a power measurement, simply flip over the slide to expose the sensor to the objective. In inverted microscopes, the transilllumination lamp can be centered on the grid to ensure the sensor is centered on the beam.


Power Meter Consoles


Our most popular power meter consoles are included here for convenience. For more information, click on the part number in the table below to view the complete presentation for each power meter console. The S170C is also compatible with the PM100USB and the PM320E consoles.


Item #PM100APM100DPM200
Console Image
(Click the Image to Enlarge)
PM100A PM100D PM200
Display Mechanical Needle and
LCD Display with Digital Readout
320 x 240 Pixel Backlit Graphical LCD Display Touch Screen Color Display
with VGA Resolution
Output Analog Needle or Digital Numeric Readout Numerical, Bar Graph, Statistics,
Simulated Analog Needle
Numerical, Bar Graph,
Trend Graph, Statistics,
Simulated Analog Needle
Data Storage and Transfer USB 2.0 Interface 1 GB External SD Memory Card,
USB 2.0 Interface
128 MB Internal Memory,
1 GB USB Flash Drive,
USB 2.0 Interface
Dimensions 7.24" x 4.29" x 1.61"
(184 mm x 109 mm x 41 mm)
7.09" x 4.13" x 1.50"
(180 mm x 105 mm x 38 mm)
6.70" x 4.93" x 1.48"
(170.2 mm x 125.1 mm x 37.5 mm)
Display Dimensions 1.9" x 0.5" (48.2 mm x 13.2 mm) Digital Display and
3.54" x 1.65" (90.0 mm x 42.0 mm) Analog Display
3.17" x 2.36"
(81.4 mm x 61.0 mm)
4.65" x 3.48"
(118.0 mm x 88.5 mm)
Achievable Detection Ranges when Used with Compatible Thorlabs Sensorsa
Optical Power Rangea 100 pW - 200 W
Wavelength Rangea 185 nm - 25 µm

These values reflect the total range of measurements possible using Thorlabs C-Series sensors. The actual range of the complete power meter (console and sensor head) will depend on the selected sensor head. For example, with the S170C, all of these consoles will be able to measure optical powers from 10 nW to 150 mW for wavelengths between 350 nm and 1100 nm.


Our Mission is to accelerate the advancement of optical technology for precision measurements and their applications from the table tops of research laboratories to standard use in communication and high technology industries. Our aim is to serve our customers. Our hope is to create a place for highly skilled people in an open environment

contact us

Tel               +966 35823441
Fax               +966 35823441
Egypt Mobile  +2 0120 7577664
KSA Mobile     +966 545 991188
Email             This email address is being protected from spambots. You need JavaScript enabled to view it.