THORLABS ACT508-250-A-ML Achromatic Doublet Lens Efl Ar /2IN/EFL MM/400-700

( Brand: Thorlabs ), ( Manufacturer Part Number: ACT508-250-A-ML ), ( Part Type: Len )

Review THORLABS Achromatic Doublet Lens /2in/efl 250mm /400-700 Nm Ar

The **Thorlabs ACT508-250-A-ML Achromatic Doublet Lens** is a high-performance optical component meticulously engineered for precision imaging, spectroscopy, and laser applications across the visible to near-infrared spectrum. Part of Thorlabs renowned **AC Series**, this lens combines two carefully selected optical glasses in a doublet configuration to minimize chromatic aberration, ensuring exceptional image quality and consistent focal performance from **400 nm to 700 nm**. With an **effective focal length (EFL) of 250 mm**, it delivers a long working distance, making it ideal for applications requiring magnification, beam expansion, or collimation in systems where space constraints are a consideration. The lens features a **2-inch (50.8 mm) clear aperture**, providing ample light-gathering capability for high-resolution imaging or high-power laser beam manipulation without significant vignetting. Constructed from **optically polished glass elements** with anti-reflection (AR) coatings optimized for the **400 700 nm range**, the lens minimizes surface reflections, enhancing throughput and reducing stray light that could degrade system performance. Its **aspheric design** further refines aberrations, ensuring near-diffraction-limited performance across the specified wavelength range, which is critical for applications in microscopy, astronomical imaging, or optical metrology. The **mechanical mount compatibility** with Thorlabs **ACT series lens tubes** allows for easy integration into existing optical setups, while the **ML (mechanical lock) variant** ensures secure alignment, reducing the risk of misalignment during handling or transportation. Whether used in a telescope, a laser beam expander, or a high-precision imaging system, this lens exemplifies Thorlabs commitment to precision engineering, offering a balance of optical clarity, durability, and versatility for demanding optical applications.

The Thorlabs ACT508-250-A-ML achromatic doublet lens is a high-quality optical component designed for use in the visible to near-infrared spectrum (400 700 nm). Below is a detailed breakdown of its pros and cons, followed by a conclusion and recommendation.

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The lens is an achromatic doublet, meaning it is designed to minimize chromatic aberration (color dispersion) across its specified wavelength range (400 700 nm). This ensures sharper, more consistent imaging and collimation across the visible spectrum, which is critical for applications like microscopy, imaging systems, or laser beam shaping.

The 2-inch diameter provides ample light-gathering capability, making it suitable for high-power or high-intensity applications where beam size or image brightness is a concern. This is particularly useful in laser systems or large-format imaging setups.

A long focal length like 250 mm is advantageous for applications requiring high magnification or long working distances, such as telescope optics, long-range imaging, or beam expansion. It also reduces the angular magnification of aberrations, improving overall image quality.

The AR coating minimizes reflective losses at the lens surfaces, maximizing transmitted light and improving efficiency in optical systems. This is especially valuable in systems where light throughput is critical, such as in imaging or spectroscopy.

Thorlabs is known for its rigorous quality control and precision optics. The lens is likely made from high-index and low-index glass materials (commonly fused silica and crown glass) that are carefully selected and bonded to achieve the desired achromatic performance. This ensures durability and reliability in demanding environments.

The lens is designed to fit Thorlabs mounting hardware, such as the ACT series mounts, which are widely used in optical labs. This compatibility simplifies integration into existing setups and reduces the need for custom adapters.

Achromatic doublets are generally robust and resistant to thermal or mechanical stress, provided they are handled with care. The cemented design (two lenses bonded together) reduces the risk of misalignment over time.

The lens can be used in a variety of applications, including beam collimation, imaging, laser systems, and optical instrumentation, due to its broad wavelength range and high optical quality.

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High-quality optical components like this achromatic doublet are expensive. The price reflects the precision manufacturing, materials, and performance guarantees. For budget-conscious projects, this may be a significant drawback, especially if the lens is only partially utilized.

The 2-inch diameter and 250 mm focal length result in a relatively large and heavy lens. This can complicate handling, mounting, and integration into compact or portable systems. Additional mechanical support may be required to prevent vibration or misalignment.

While the lens is optimized for 400 700 nm, its performance outside this range may degrade. For applications requiring broader spectral coverage (e.g., UV or near-IR beyond 700 nm), a different lens design (such as an apochromatic doublet or specialized IR lens) would be necessary.

Achromatic doublets, like all precision optics, require careful alignment to achieve optimal performance. Misalignment during mounting or use can introduce aberrations or reduce image quality. This may require additional optical tables, mounts, or alignment tools, adding complexity to the setup.

The AR coating is delicate and can be damaged by abrasive cleaning methods or improper handling. Scratches or coating degradation can reduce transmission efficiency and introduce artifacts. Careful handling and cleaning (e.g., using lens tissues and appropriate solutions) are essential.

Like most optical components, this lens may exhibit slight performance variations with temperature changes. While the materials are chosen to minimize thermal aberrations, significant temperature fluctuations could still affect focal length or image quality in some applications.

Thorlabs offers a range of standard lenses, but customizing parameters such as focal length, diameter, or coating for non-standard wavelengths may require additional lead time or higher costs. This lack of flexibility could be a limitation for specialized applications.

In systems with large field angles or off-axis imaging, the lens s finite aperture (2 inches) may cause vignetting (loss of light at the edges of the image). This could require additional apertures or optical elements to mitigate.

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The Thorlabs ACT508-250-A-ML achromatic doublet lens is an excellent choice for applications requiring high optical performance in the visible spectrum (400 700 nm), particularly where chromatic aberration correction, large aperture, and long focal length are critical. Its precision manufacturing, durability, and compatibility with Thorlabs ecosystem make it a reliable and versatile component. However, its cost, size, and sensitivity to alignment and handling may pose challenges for certain applications or budgets.

For projects where the specified wavelength range, aperture, and focal length align with requirements, this lens is highly recommended. If the application involves broader spectral coverage, compact designs, or lower budgets, alternative lenses or optical designs may need to be considered.

- Your application requires high-quality imaging or beam shaping in the 400 700 nm range.

- You need a large aperture (2 inches) and long focal length (250 mm) for high-power or high-magnification setups.

- You are working within a Thorlabs optical system and can accommodate the lens s size and cost.

- Chromatic aberration correction is a priority, and the lens s performance meets your spectral requirements.

- Your budget is constrained, and a lower-cost lens with similar but slightly reduced performance would suffice.

- Your application requires operation outside the 400 700 nm range, necessitating a different lens design.

- Space or weight constraints make the lens impractical for your setup.

- You need customization beyond standard specifications, which may not be available from Thorlabs.

Details:

part #: act508250a price

• $749.24

specifications microscopepartzo:

• brand: Thorlabs
• mpn: Act508-250-a-ml
• part type: Len

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• sold: 0
• quantity: 1
• availability: In Stock
• started: May 10, 2026
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general microscopepartzo:

• condition: Used
• Medical/Lab Equipment Attachments Accessories > Microscope Parts Accessories > Other Microscope Parts Accessories

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