PD300-TP | Laser Photodiode Sensors | Power Sensors - Ophir
PD300-TP | Laser Photodiode Sensors | Power Sensors - Ophir



The PD300-TP is a thin profile photodiode laser measurement senso with a switchable filter feature and a 10x10mm aperture.  With filter out, its spectral range is 350 - 1100nm and its power measuring range from 50pW to 3mW. With filter in, its spectral range is  400nm - 1100nm and its power range from 20µW - 1W. The sensor comes with a 1.5 meter cable for connecting to a meter or PC interface.


  • N.A.
  • 10x10mm
  • 350-1100nm
  • 50pW-1W
  • N.A.
  • N.A.
  • 175 L x 21 W x 19 D (mm)
  • 100μJ
  • 10W/cm²
  • 0.2 s
  • N.A.
  • N.A.
  • 1W
  • N.A.
  • CE, China RoHS
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How do I take off the removable filter from the PD300?

Removing External Filter from PD300:

Step 1 – Starting position


Step 2


Step 3

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Can I use a sensor from the PD300 family to measure average power of pulsed lasers?

In general yes, but several technical issues need to be kept in mind (most of which are results of the fast physical response time of these sensors):

  • The pulse rate should be more than about 30Hz, otherwise the reading is unstable. At higher pulse frequencies, the sensor will respond as if the beam were CW. 
  • It is possible for a pulsed beam to have average power within the sensor spec and yet have the energy of the pulses themselves be high enough to cause a momentary saturation of the sensor. It is important to be sure that pulse energy is also within sensor spec (the parameter "Max pulse energy" is included in all specs for the PD300 family, for just this reason).
  • The beam diameter should be no less than about 1mm .
  • The average power and power density restriction in the spec should not be exceeded


Note: At the maximum pulse energy limit given in the spec, the reading will be saturated by about 5%, i.e. the reading will be about 5% lower than it should be. At 1/3 the maximum, the saturation will be about 1%.

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Can a lost PD300 filter be replaced?

Technically it could be replaced, but it is not just a matter of replacing the filter. Since the PD300 is a "calibrated" sensor it requires that the filter also be "calibrated". Especially since the PD300 response varies with wavelength, it requires that both the PD300 and the filter be calibrated over the entire spectral range with a monochromator. Because of the cost to calibrate the replacement filter with the PD300 sensor, we recommend purchasing a new PD300 sensor when a replacement filter is needed.

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The total error when using a PD-300 head is listed as +/- 3%. Is that 3% of the reading or 3% of the total range?

It's +/-3% of the reading from full scale down to 5% of full scale. Below 5% of full scale one should switch to next range down for the best accurate linear results.

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Do I need to recalibrate my instrument? How often must it be recalibrated?

Unless otherwise indicated, Ophir sensors and meters should be recalibrated within 18 months after initial purchase, and then once a year after that.

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Can I use a PD300 photodiode sensor to measure power of a scanned beam?

For measuring power of a scanned beam we recommend using the BC20, and not the PD300. Since a scanned beam will spend only a fraction of the time of each scan on the detector, the average power measured by the detector will correspondingly be only a fraction of the actual power of the beam. The BC20 is specially designed for such applications by having a peak-hold circuit integrated in its electronics.

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Can I use a PD300 sensor inside a thermal chamber, in which the temperature cycles beyond the recommended operating temperature range?

It should be okay, as long as:

  • the wavelength is not near the long wavelength limit where the PD300 has a large temperature dependence;
  • there is no condensation on the window of the detector which could interfere with the beam and affect the reading.

We suggest the customer does an experiment with a stable laser source (such as a pointer laser) shining in through a window onto the detector while the unit is temperature cycled to see if the reading changes. The final measurement should be back at the original temperature so as to make sure the laser hasn’t changed.

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FAQ: Photodiode Sensors for measuring very low laser powers FAQ: Photodiode Sensors for measuring very low laser powers
How to measure power of very low power pulsed laser beams How to measure power of very low power pulsed laser beams How to measure power of very low power pulsed laser beams

When using a photodiode laser power sensor to measure very low power pulsed beams (nW to mW), there are some issues you need to be aware of. This video shows you how to avoid some common problems and ensure maximum accuracy.

FAQ: Sensors for Measuring Laser Power FAQ: Sensors for Measuring Laser Power FAQ: Sensors for Measuring Laser Power

In this short “Basics” video we review in general how one goes about measuring laser beam power, so that you’ll have a clear basic understanding of what the different sensor types are, and when you would use which type.

Effects of Incidence Angle on Measurements Effects of Incidence Angle on Measurements Effects of Incidence Angle on Measurements

Are you measuring a laser beam coming at an angle correctly?
Ever wonder how your laser power measurements are affected by your beam’s angle of incidence?
In this video, you will learn to what degree a beam’s incidence angle matters, and for which sensor types this should be taken into account.

In this short “Basics” video, we review in general the use of photodiode sensors for measuring very low laser powers.


Tutorials and Articles

Laser Power Sensors introduction

As described in the general introduction, the thermopile sensor has a series of bimetallic junctions. A temperature difference between any two junctions causes a voltage to be formed between the two junctions. Since the junctions are in series and the «hot» junctions are always on the inner, hotter side, and the «cold» junctions are on the outer, cooler side, radial heat flow on the disc causes a voltage proportional to the power input. Laser power impinges on the center of the thermopile sensor disk (on the reverse side of the thermopile), flows radially and is cooled on the periphery. The array of thermocouples measures the temperature gradient, which is proportional to the incident or absorbed power. In principle, the reading is not dependent on the ambient temperature since only the temperature difference affects the voltage generated and the voltage difference depends only on the heat flow, not on the ambient temperature.


Common Reasons for Photodiode Sensor Damage or Out of Tolerance Conditions

We have included this document with your recent calibration order because we have noticed an out of tolerance condition obtained from your equipment when returned for calibration. This document was created to assist our valued customers in the proper care and maintenance of Ophir photodiode sensors. The following information is for reference only. If you have any reason to believe that the sensor is no longer performing within the original specifications, we always recommend that you send it in for repair and/or recalibration by our trained technicians to bring the unit back to the proper NIST traceable standards.

Ophir photodiode sensors can be used for many years without any repairs when used with the proper laser optical setup. Many of our customers have sensors that are using their original absorber that are over ten years of age. We hope that this document will enable you to also enjoy the long life and reliable results that Ophir- Spiricon is known for.


How to Properly Select a Laser Power or Energy Sensor

The selection of a sensor to accurately measure the power of a laser or energy of a pulsed laser can seem like a simple and easy procedure. However, many times the selection process is limited to choosing a sensor that only meets the range of power or energy to be measured, leaving out several other essential criteria of the laser specifications; that without their consideration, can allow the wrong sensor to be selected, the laser to be measured inaccurately and likely to cause the sensor to fail prematurely.

Watch Our Laser Measurement Video


Effect of Ambient Conditions on Laser Measurements

We are often asked about the specified ranges of various ambient conditions (temperature, humidity, etc.) for Ophir instruments. In this article we will clarify the effects of these conditions on laser measurements, so you’ll be able to use your Ophir laser measurement instrument effectively.


Online Sensor Finder

The online sensor finder now gives comments to help the user find a solution in case he does not succeed in doing so. Examples below: Read more...