FP-500L Off-Axis Parabolic Collimator – 500mm Focal Length

Off-Axis Reflective Optical Structure

The FP-500L off-axis Parabolic Collimator uses a primary off-axis mirror and a secondary plane mirror to deliver unobstructed parallel beams. Because the primary and secondary mirrors do not share the same axis, the light path avoids obstruction and minimizes stray reflections. This layout ensures the Φ100 mm clear aperture remains fully open, while the reflective design maintains ≤ 5″ beam parallelism, securing stable alignment and clean optical performance for various measurement setups.

Optical Precision and Lens Collimator Characteristics

Its optical configuration includes a high-precision quartz-glass main mirror with aluminum + silicon coating (with optional gold/silver/dielectric alternatives). The wavefront aberration (system) reaches RMS ≥ 1/15λ @ 632.8 nm, and the primary mirror surface achieves RMS ≤ 1/40λ. Reflectivity is ≥ 85%. The lens collimator aspect ensures consistent optical quality across the full visible range, maintaining focal accuracy within ±1%, and supporting wide field of view (≥ 3.2°) applications.

Modular Testing Accessories and Application Flexibility
The instrument comes with standard accessories: two filters (600 nm orange, 532 nm green), a neutral attenuator (430–730 nm), 12 visible reticles (crosshair, resolution, star-point types), a USAF 1951 resolution reticle, and a 12 V/30 W halogen light source. For infrared and advanced testing, it supports customized reticles for MRTD, MDTD, SRF, distortion, outline, square pattern, and NETD/FPN/SITF tasks. The modular target plate frame allows fast replacement and alignment of different test patterns, making it suitable for image calibration, optical axis diagnostics, and beam expansion tasks in laboratories and product inspection lines.

Product Advantages

Unobstructed Illumination and Beam Coherence

The off-axis design of the Parabolic Collimator ensures the light path is free from central mirror obstruction, producing a clean, high-coherence beam ideal for precise optical alignment and instrument calibration. The configuration reduces stray light and maintains consistent beam uniformity.

High Surface Accuracy and Reflectivity

With its primary mirror achieving RMS ≤ 1/40λ and the system maintaining RMS ≥ 1/15λ, the collimator ensures wavefront integrity. Reflectivity ≥ 85% ensures light throughput remains high. The coating is robust against oxidation and spectral drift, preserving long-term performance in the lens collimator system.

Versatile Configuration from a Trusted Manufacture

As a professional collimator manufacture, YuLing Technology integrates precise polishing, optical alignment, and quality control in every unit. The modular structure and accessory compatibility support a wide range of optical tasks—beam expansion, image calibration, infrared testing—while ensuring reliable long-term stability.

Optical path diagram：

1. The main reflector adopts an off-axis surface mirror, select the appropriate off-axis, so that the reflected optical path deviates from the optical axis, avoids the secondary reflector from interfering with the light-passing optical path, and ensure that the φ100mm light-permeable area is unobstructed.
2. The secondary mirror adopts a plane reflector, which undertakes the reflected light path of the main reflector and turns the light path, so that the reflected light path is located on the side of the light outlet, which is convenient for later debugging and use.
3. The focal plane position is the target surface installation position. Each target plate is installed in the dividing plate frame separately. Through later debugging, each target plate is placed in the focal surface position after separate assembly to realize the target plate replacement function.

Standard Components:

1. Collimator Main Unit: 1 set
2. Filters: 2 pieces (Orange, center wavelength 600nm; Green, center wavelength 532nm)
3. Attenuator: 1 piece (Neutral Attenuator 430–730nm)
4. Visible Reticles: 12 pieces(Crosshair Reticles*1,Resolution Reticles*5:1#/2#/3#/4#/5#,Star Point Reticles*5: 0.1/0.2/0.01/0.02/0.05,Porro Board*1)
5. USAF 1951 Resolution Reticle: 1 piece
6. Light Source Assembly: 1 set( 12V30W Halogen Light Source)

Custom Components (Applicable to Infrared Reticles):

Infrared targets are formed by machining various patterns into thin metal plates. When illuminated by a blackbody source, the thermal imager under test observes sharp target patterns against a uniform background. A variety of standard infrared targets are available for customization.

Examples of Targets:

1. Four-Bar Target: For Minimum Resolvable Temperature Difference (MRTD) testing.
2. Circular Target: For Minimum Detectable Temperature Difference (MDTD) testing.
3. Slit Target: For Slit Response Function (SRF) testing.
4. Cross-Circle Target: For axis alignment, aiming, and focusing.
5. Distortion Target: For testing camera distortion in image generation.
6. Outline Target: For evaluating target recognition range of the camera under test.
7. Square Target: For testing Noise Equivalent Temperature Difference (NETD), Fixed Pattern Noise (FPN), Signal Transfer Function (SITF), and Aperiodic Transfer Function (ATF).

External dimensions:（Unit: mm）

About Us

YuLing Technology, headquartered in Chongqing, China, is a specialist in precision optical and photoelectric measurement instruments. With a research and development center in Xi’an, the company designs and manufactures collimators, autocollimators, optical benches, and calibration systems. Its client base spans aerospace, defense, metrology, and advanced imaging sectors. YuLing combines optical engineering, mechanical precision, and electronic integration to deliver accurate, stable, and customizable optical solutions. Upholding principles of quality and integrity, the company provides full technical support and tailors instruments to meet demanding application needs.Contact YuLing today to request the FP-500L specifications or discuss your optical calibration project!

FAQ – Frequently Asked Questions

What beam parallelism does this Parabolic Collimator offer?

It achieves ≤ 5″ parallelism, validated via interferometric testing.

What is the effective aperture size?

The clear aperture is Φ100 mm without central obstruction.

Which wavelength range does the lens collimator aspect support?

The design supports 380–780 nm with high optical fidelity.

Can I use infrared or laser targets with it?

Yes, the system supports customized infrared reticles (MRTD, MDTD, SRF) and laser-compatible targets.

What is the delivery time for a configured unit?

Lead time is typically 4–6 weeks depending on accessory configuration and custom requirements.