Compare Model Drawings, CAD & Specs Availability Price
1938-R Advanced Optical Power & Meter, Benchtop, Single Channel
7 Weeks
7 Weeks
2938-R Advanced Optical Power & Meter, Benchtop, Dual Channel
6 Weeks
6 Weeks


  • Bandwidth
    Up to 200 kHz
  • Measurement Rate
    Up to 10 kHz
  • Compatible Detectors
    Photodiode: 918D, 818DB, 819C/D, 818-MSCOPE
    Thermopile: 919P, PEPS
    Pyroelectric: 919E, LIAD
  • Detector Connector
    15-pin D-Sub type Male
  • Detector Input
    Photodiode & Thermopile: 8nA - 25mA full scale in 20 ranges
    Pyroelectric: 0 - 5V full scale
  • Sampling Rate
    Photodiode: 10 kHz fast-mode, 15 Hz slow-mode
    Thermopile: 15 Hz
    Pyroelectric: 25 kHz
  • Gain Ranges
    10 decades
  • Analog Output Connector
    BNC socket
  • Analog Output
    User selected 1, 2, 5, or 10 V full-scale, 0.03% resolution, 100Ω impedance
  • Data Storage
    2 GB internal memory, External storage defined by user supplied flash drive (USB A)
  • Computer Interfaces
    USB B, RS-232
  • Display Type
    7 in. TFT LCD (1024x600) Touchscreen
  • LCD Backlight
    LED, user adjustable brightness
  • Photodiode Measurement
    Power, exposure, low frequency power, fast power, amps
  • Thermopile Measurement
    Average power, single shot energy, pulsed power
  • Pyroelectric Measurement
    Pulse energy (every pulse up to 25 kHz), average power, exposure
  • Power Requirements
    ~100-240V AC 50-60Hz, Max 40 W
  • Dimensions
    216 x 296 x 147 mm
  • Weight
    2.8 kg
  • Operating Temperature
    5 to 40°C, <70% RH


Most Advanced Optical Power and Energy Meter in The Market

The all new 1938-R and 2938-R power meters, inheriting most of the advanced functions available in x936-R series, have been redesigned with the up-to-date CPU, touch screen, Android OS, and high bandwidth electronics boards. The new power meters are one of the most powerful, fast, and versatile power meters in the market. Beautifully designed user interface allows unprecedent speed of measurements along with various graphical and numerical presentation of the data.

Ideal for High Speed, Modulated Light Measurements

Depending on the range, x938-R power meter has up to 200 kHz bandwidth for the 818, 918D, or 819C/D series photodiode detectors. It allows up to 10 kHz rate, time-stamped data logging to the on-board memory or an external USB memory, showing more details about the characteristics of the light source. To fully utilize the high bandwidth operation, x938-R has analog output where the raw signal can be directly sent out to an oscilloscope or a DAQ (data acquisition) board. In addition, when connected to a 919E series pyroelectric sensor, every single pulse up to 25 kHz can be logged.

Time-stamped Data Acquisition at up to 10 kHz

Even though x936-R’s 10 kHz data measurement rate was already impressive, the new x938-R optical power meters made an improvement by adding a time stamp to the data, thereby knowing exactly when the measurements were taken. The log files can be easily set up and recorded in either the 2 GB on-board memory or on a USB thumb drive. Once the log files are created, the text data or the graphics file can be viewed within the instrument.  

Full Color 7” Touch Screen with Intuitive User Interface

1024 x 600 pixel high brightness, full color 7” touch screen provides the feel of using a tablet, making the menu maneuvering at one’s fingertip. With the clearly legible display, various selections of information and graphs are visually appealing and easy to read even at a distance, making the instruments more helpful in complex measurement situations. The user interface is beautifully designed so that advanced features such as advanced graphing, mathematical functions, offsetting, scaling, laser tuning, logging can easily be accessed and utilized during measurements and experiments.

Seven Analog Filter and Multiple Averaging Settings

With seven analog filters, ranging from 0.5 Hz to 250 kHz, and the averaging function, ranging from one second to one hour of moving average, one can configure the power meter for either the stable average power measurements of a continuous wave light source, fast tracking of a rapidly changing optical power level, or the peak-to-peak measurements of a modulated signal. The analog filter is an electronic low pass filter used to eliminate high frequency noise, while averaging allows smoothing the data by applying moving average of the obtained data. By adjusting these settings, it is possible to make stable power measurements while the beam is modulated. 

Trigger In and TTL Out for Synchronized Measurements

X938-R power and energy meters are equipped with Trigger In and TTL Out connectors for synchronized measurements. Trigger In can be an external TTL signal, or a button available from the meter, or a computer command. TTL Out gives out either 0 V or 5 V to signal the status of the present measurement to a device connected via TTL Output. It can also be set to generate an output when the meter encounters an error such as power reading is over-range or saturated. 

Various Communication and Signal Out Modes

For the computer communication, USB and RS-232 (max baud rate 115,200) are available. In the future development, Wi-fi and ethernet are to be introduced as well, to allow the user more choices of computer control of the instrument. In addition to the aforementioned Trigger In and TTL Output, fast analog output directly coming from the analog board allows the full bandwidth available with the power meter.

Multiple Background Color and Language Support

With the all new 1938-R and 2938-R advanced optical power and energy meters, you can set multiple background colors and the intensity level most suitable for the laser safety goggles you are wearing. You can also choose from 9 languages to operate, including English, Chinese, German, Korean, Spanish, French, Japanese, Italian, and Russian.

PMManager™ Application Software

PMManager™ is a powerful application software controlling and taking measurement data. It turns a PC into a laser power multi-channel analysis workstation. The PMManager software features include: extensive graphic display of data, advanced measurement processing, data logging for future review, printing of graphs and data, and the ability to connect additional devices during active measurements. The PMManager software package includes the latest PMManager user manual, the COM object manual, the available user command lists, and automation examples written in various programming languages.  Please see the PMManager Tutorial for more details regarding its capabilities.