UV Air-Spaced Achromatic Doublets, AR-Coated: 245

Overview
Performance
Feedback

Specifications
Wavelength Range	245 - 400 nm
Design Wavelengths	282.5, 325.0, and 367.5 nm
Surface Quality	10-5 Scratch-Dig (to Prevent Scattering from High-Power Sources)
Clear Aperture	Ø20 mm
Focal Length Tolerance	±1% at 325.0 nm
Centration	<3 arcmin
AR Coating	R_avg < 0.5% from 245 - 400 nm
Housing	Ø1" 6061-T6 Aluminum Barrel

Zemax Files
Click on the red Document icon next to the item numbers below to access the Zemax file download. Our entire Zemax Catalog is also available.

Click to Enlarge
Air-Spaced Achromatic Doublet in an SM1L30C Slotted Lens Tube with Two SM1RR Retaining Rings

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Features

Air-Spaced Design Provides Excellent Aberration Performance
Ø20 mm Clear Aperture
1" Outer Diameter for Mounting Inside a Ø1" Lens Tube
AR Coating for the 245 - 400 nm Range

Thorlabs' Air-Spaced Achromatic Doublets are designed to provide superior spherical and chromatic aberration correction. Air-Spaced Doublets have an optical design with four degrees of freedom. These extra variables allow the performance of these air-spaced doublets to exceed the performance of equivalent cemented doublets in some cases. For details, please see the Performance tab. The air-spaced design is also highly resistant to laser damage, since no cement is utilized in the fabrication process.

The doublets are pre-mounted in an aluminum barrel with tight tolerances on lens and barrel diameter to minimize the effects of lens decentering. Each mount includes an engraving with the part number, AR coating wavelength, focal length, and the direction of light propagation required to collimate a point source. The mount has a 1" outer diameter for mounting inside a Ø1" lens tube (as shown in the photo to the right).

Note: We do not recommend disassembly of these lenses, as this may affect performance.

Air-Spaced Doublets Selection Guide
UV (245 - 400 nm)	D (1.65 - 3 µm)
Visible (350 - 700 nm)	E (3 - 5 µm)
NIR (650 - 1050 nm)	F (8 - 12 µm)
Laser-Line (532 & 1064 nm)

UV Air-Spaced Achromatic Doublet Performance

The tables below contains links to pop-ups with plots containing the theoretical performance of each air-spaced achromatic doublet.

Item #	Focal Shift Plots	Wavefront Error Plots	Spot Radius Plots
ACA254-100-UV
ACA254-150-UV
ACA254-200-UV

Posted Comments:

Pawel Czuma (posted 2019-10-24 14:01:52.707)

Please answer my following questions: 1.) Is It possible to make UV Air-Spaced Achromatic Doublets uncoated? What will be transmission of such doublet from 190 to 400nm? What will be price? 2.) Is it possible to make such UV Air-Spaced Achromatic Doublets uncoated for WD=25mm and focus of approx 33mm? Best Regards, Pawel

YLohia (posted 2019-10-24 02:30:33.0)

Hello Pawel, thank you for contacting Thorlabs. Custom lenses can be requested by emailing our Tech Support team. We will reach out to you directly to discuss the feasibility of offering this.

saurabh (posted 2018-03-22 06:08:11.03)

I need this product Qty. 2 Also do you have similar focal lens for f=90mm ?

tfrisch (posted 2018-03-22 09:47:20.0)

Hello, thank you for contacting Thorlabs. Our Sales Team can send you a quote for 2pcs of ACA254-100-UV, and I will reach out to you directly about price, lead time, and minimum order quantity for a 90mm focal length version.

scottie730318 (posted 2014-05-15 00:57:23.963)

The ACA254-100-UV has any Mounting Thread on the lens housing (i.e. SM1)? thanks

jlow (posted 2014-05-14 01:29:15.0)

Response from Jeremy at Thorlabs: There's no mounting thread on the lens housing. The outer diameter is Ø1" so you can put this in any mount that can accept Ø1" optics with >0.63" thickness.

scottie730318 (posted 2014-05-15 00:17:31.917)

Each mount includes an engraving with the part number, AR coating wavelength, focal length, and the direction of light propagation required to collimate a point source. It indicated that the direction of arrow go right, the point source must be put in the left to obtain the collimated beam? When the point source put in the left of lens, the collimating beam can be obtained on the right side.

jlow (posted 2014-05-14 01:28:15.0)

Response from Jeremy at Thorlabs: When the arrow points to the right, the point source should be put on the left for best performance.

user (posted 2013-02-12 13:23:25.14)

Which is the damage threshold? Thanks

jlow (posted 2013-02-14 09:58:00.0)

Response from Jeremy at Thorlabs: These lenses are being tested and we will update the website once we have tested values. In the meantime, you could use the value for our -UV coated UVFS window as a guideline, which is 5.0 J/cm^2 (355 nm, 10 ns, 10 Hz, Ø0.350 mm).

245 - 400 Air-Spaced Achromatic Doublets

Item #	f (mm)	R₁ (mm)	R₂ (mm)	R₃ (mm)	R₄ (mm)	t_c1^a (mm)	t_c2^b (mm)	Air Gap^c (mm)	L (mm)	WD (mm)
ACA254-100-UV	102.9	30.33	-26.88	-25.85	117.77	7.10	6.00	0.25	16.1	85.8
ACA254-150-UV	150.0	56.55	-24.17	-23.80	Plano	6.35	2.50	0.54	13.0	138.9
ACA254-200-UV	200.005	138.00	-26.56	-25.69	-151.4	4.50	4.25	1.30	13.6	190.0

a. Left lens center thickness in the reference drawing. b. Right lens center thickness in the reference drawing. c. Center air spacing between the lenses.

Item #	Left Lens Material^b	Right Lens Material^b
ACA254-100-UV	CaF₂	UV Fused Silica
ACA254-150-UV	CaF₂	UV Fused Silica
ACA254-200-UV	CaF₂	UV Fused Silica

The shaded region represents the specified coating range of the lenses. Click here to download transmission data.
"Left" and "Right" refer to the orientations of the lenses in the Reference Drawing found by clicking on the info icon above.

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UV Air-Spaced Achromatic Doublets, AR-Coated: 245 - 400 nm

Features

UV Air-Spaced Achromatic Doublet Performance

245 - 400 Air-Spaced Achromatic Doublets