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[Basic Optical Skills] Reflector Adjustment Method

March 16, 2026 Shopify API WaveQuanta Technical Resources

Abstract: Using reflectors to deflect light paths is one of the most familiar techniques for professionals in the optical field; and it is even more familiar to experienced laser engineers and scientists. But as a beginner who has just stepped into a laboratory or company, it may not be a smooth journey. I hope this article can help beginners quickly understand the skills, save time and improve efficiency.

When I first entered the laboratory, I saw the calmness and calmness with which my brothers and sisters adjusted the light path. I watched with admiration and felt envious. Fortunately, I got advice from my long-time friend, tried it several times, and after many twists and turns, I finally understood the principle, so easy.

Figure 1 Entry-level light path adjustment

Figure 1 is the simplest dual-mirror positioning structure, using two mirrors M1 and M2 to determine a certain light AB. Under normal circumstances, two diaphragms are placed at A and B to locate the direction and position of the light path. By repeatedly adjusting M1 and M2, the goal is finally achieved. But how can we achieve the goal quickly and accurately? There are two key points:

1. Adjust the distance between the two apertures A and B as long as possible to improve the accuracy of the adjustment.

2. The first aperture A is as close to M2 as possible, so that it can be adjusted in about one or two rounds, which greatly improves efficiency.

The principles behind the above two techniques: the center position of the light spot on the surface of M2 and the attitude of M2 uniquely determine the position (near field) and direction (far field) of the light path. The adjustment of all reflector light paths is based on this principle.

So, can it be fast and accurate again in complex large-scale optical paths? The answer is yes, let me introduce you to an advanced method. I highly recommend a light-dimming artifact (not an advertisement): the horizontal line mark. This dimming artifact was originally most commonly used on construction sites, and now it has become a staple in high-end laboratories. The advantage of the horizontal marking instrument is that it avoids the safety hazards of using a steel ruler (reflection of laser light from the metal surface), thereby achieving the purpose of determining the height and horizontal position of the optical path.

As can be seen in Figure 2, it emits two automatically horizontal and vertical spatially extended laser lines (left) or several horizontal and vertical points (right). It is usually fixed on a tripod to adjust the height.

[Basic Optical Skills] Reflector Adjustm - Figure 2

Figure 2 Horizontal reticle: linear (left), dotted (right)

In the process of adjusting the light path, first adjust the horizontal line of the reticle (tripod or lifting platform) to the appropriate height (can be determined in advance with a ruler or aperture), and the vertical reticle is transmitted in the direction of the design (generally along the center of the hole of the optical platform), and then you can start your own free style.

Some people may question that using the aperture as a daily adjustment reference is too cumbersome. Sometimes it is even difficult to judge the center of the beam, especially when using the aperture in vacuum and high energy is simply impossible. In this regard, it is recommended to try an improved optical path adjustment method: near-far field imaging method. As shown in Figure 3, the basic principle is the same. The imaging system composed of lenses L1 and L2 is used to image the M2 surface onto the CCD camera C1, and the center of the beam is calibrated to determine the near field; the CCD camera C2 is used to receive the focus of L1 to determine the far field. At this point, the direction and position of the beam coming out of M2 are uniquely determined. In actual use, use M1 to adjust the center of the beam to the designated position of C1, and then use M2 to adjust the center of the beam to the designated position of C2. One round is enough.

Benefits of using this method:

1. The directivity change of the optical path can be monitored in real time without changing the actual optical path;

2. At the same time, it can also be equipped with an automatic calibration system for real-time feedback and adjustment;

[Basic Optical Skills] Reflector Adjustm - Figure 3

3. Suitable for the adjustment and monitoring of the optical path under vacuum conditions, but it needs to be equipped with a vacuum adjustable knob;

4. High-end, high-end, suitable for showing off!

Regarding construction and usage skills:

[Basic Optical Skills] Reflector Adjustm - Figure 4

1. The surface of M2 must be strictly imaged on C1. The imaging system has been designed in advance. You can place a business card (or imaging card) on the surface of M2, use a flashlight to illuminate the surface, and gradually move the position of C1 until a clear image is obtained;

2. C2 must be at the focus position. There is no need to worry too much about the quality of the focus, just clear the center;

3. Determine the focal lengths of L1 and L2 according to the size of the CCD chip, and use a positive lens, otherwise imaging will not be possible;

4. In terms of economic costs, the lenses, beam splitters, CCD cameras and beam splitters in the optical path do not require high quality requirements;

5. When used in vacuum conditions, the CCD power-on time must be strictly controlled to avoid damage to the camera due to excessive heat.