Selection Guide for Neutral Density Filters
Selection Guide for Neutral Density Filters		Absorptive
Uncoated (400 - 650 nm)	Mounted
Uncoated (400 - 650 nm)	Unmounted
Uncoated (800 - 2600 nm)	Mounted
Uncoated (800 - 2600 nm)	Unmounted
AR-Coated (350 - 700 nm)	Mounted
AR-Coated (350 - 700 nm)	Unmounted
AR-Coated (650 - 1050 nm)	Mounted
AR-Coated (650 - 1050 nm)	Unmounted
AR-Coated (1050 - 1650 nm)	Mounted
AR-Coated (1050 - 1650 nm)	Unmounted
Reflective
N-BK7 (350 - 1100 nm)	Mounted
N-BK7 (350 - 1100 nm)	Unmounted
UV Fused Silica (200 - 1200 nm)	Mounted
UV Fused Silica (200 - 1200 nm)	Unmounted
ZnSe (2 - 12 µm)	Mounted
ZnSe (2 - 12 µm)	Unmounted
Variable Reflective
Neutral Density Filter Kits

Features

Ø1" Mounted Reflective (Metallic) ND Filters Available
Ø1/2", Ø25 mm, Ø2", or 2" x 2" Absorptive ND Filters Available
10 Filters Included with Optical Densities from 0.1 - 4.0 (12 Filters from 0.1 - 5.0 for the NEK02)
Mounted Versions are Housed in Labeled SM Threaded Lens Tubes
Labeled Inserts Hold Filters Securely in Storage Box

Thorlabs' Reflective and Absorptive Neutral Density (ND) Filter Kits offer our most popular filters prepackaged in convenient metal storage boxes. Refer to the Specs (Reflective) and Specs (Absorptive) tabs above for detailed information about the filters included with each kit.

The Ø1/2" Absorptive ND Filters are mounted in SM05 series lens tubes, the Ø25 mm Metallic and Absorptive ND Filters are mounted in SM1 series lens tubes, and the Ø2" absorptive ND filters are mounted in SM2 series lens tubes. In all cases the housing is engraved with the optical density. Same-size lens tubes are stackable, making it possible to create an additive optical density effect. The Absorptive 2" Square Filters can be mounted in our stackable filter holders, also making it possible to create an additive optical density effect.

Each set of filters is housed in a metal box for convenient storage and transportation. Additional storage boxes designed to house mounted Ø25 mm filters (KT01), mounted Ø2" filters (KT06), or unmounted 2" square filters (KT03) can be purchased separately.

Reflective ND Filters

NDK01
Substrate	N-BK7
Unmounted Diameter	25.0 ± 0.5 mm (unmounted)
Unmounted Thickness	1.0 ± 0.25 mm (unmounted)
Clear Aperture	90% Diameter
Flatness	<5λ over Diameter
Surface Quality	40-20
Parallelism	<3 arcmin
Damage Threshold (CW)	0.75 W/cm²

NDK01 Kit Contents
Item #	Optical Density*	Nominal Transmission (T)	Minimum T (350 - 800 nm)	Maximum T (350 - 800 nm)	Minimum T (800 - 1200 nm)	Maximum T (800 - 1200 nm)
ND01A	0.1	79%	77%	81%	71%	87%
ND02A	0.2	63%	61%	65%	57%	69%
ND03A	0.3	50%	48%	52%	45%	55%
ND04A	0.4	40%	38.5%	41.4%	36%	44%
ND05A	0.5	32%	30.5%	33.5%	28%	36%
ND06A	0.6	25%	23.5%	26.5%	21%	29%
ND10A	1.0	10%	9%	11%	6.5%	13.5%
ND20A	2.0	1.0%	0.8%	1.2%	0.5%	1.5%
ND30A	3.0	0.10%	0.06%	0.14%	0.1%	0.25%
ND40A	4.0	0.01%	-	0.02%	-	0.02%

Reflective ND Filter Transmission

UV Reflective ND Filters

NUK01
Substrate	UV Fused Silica
Front Surface Coating	Inconel
Spectral Range	200 - 1200 nm
Optical Density Tolerance	5%
Diameter	Ø25.0 +0.00/-0.50 mm
Thickness	1 ±0.25 mm
Surface Quality	40-20
Surface Flatness	<5λ
Damage Threshold	0.75 W/cm²
Operating Temperature	<100 °C

NUK01 Kit Contents
Item #	Optical Density
NDUV01A	0.1
NDUV02A	0.2
NDUV03A	0.3
NDUV04A	0.4
NDUV05A	0.5
NDUV06A	0.6
NDUV10A	1.0
NDUV20A	2.0
NDUV30A	3.0
NDUV40A	4.0

NDUV Transmission

Specifications

Item #	NEK02	NEK01	NEK03	NEK01S
Filter Diameter	Ø1/2"	Ø25 mm	Ø2"	2" X 2"
Number of Filters in Kit	12	10	10	10
Diameter Tolerance (mm)	+0.0 / -0.25
Clear Aperture	90% Outer Diameter			90% of Total Area
Surface Flatness @ 633 nm	λ/10
Scratch-Dig	40-20
Parallelism	3 arcmin	10 arcsec
Substrates	NG1, NG4, NG9, or NG11 (Schott)

Kit Contents

NEK02	NEK01	NEK03	NEK01S	Optical Density (@ 633 nm)	Theoretical Transmission (@ 633 nm)	Substrate Thickness*	Substrate
Ø1/2"	Ø1"	Ø2"	2" x 2"	Optical Density (@ 633 nm)	Theoretical Transmission (@ 633 nm)	Substrate Thickness*	Substrate
NE501A	NE01A	NE2R01A	NE201B	0.1 ± 0.01	77.6 to 81.3%	0.56 mm	NG11
NE502A	NE02A	NE2R02A	NE202B	0.2 ± 0.01	61.7 to 64.6%	1.43 mm	NG11
NE503A	NE03A	NE2R03A	NE203B	0.3 ± 0.01	50%	2.30 mm	NG11
NE504A	NE04A	NE2R04A	NE204B	0.4 ± 0.02	40%	0.71 mm	NG4
NE505A	NE05A	NE2R05A	NE205B	0.5 ± 0.03	32%	0.91 mm	NG4
NE506A	NE06A	NE2R06A	NE206B	0.6 ± 0.04	25%	1.10 mm	NG4
NE510A	NE10A	NE2R10A	NE210B	1.0 ± 0.06	10%	1.89 mm	NG4
NE513A	-	-	-	1.3 ± 0.08	5%	2.48 mm	NG4
NE520A	NE20A	NE2R20A	NE220B	2.0 ± 0.10	1%	1.40 mm	NG9
NE530A	NE30A	NE2R30A	NE230B	3.0 ± 0.15	0.1%	2.11 mm	NG9
NE540A	NE40A	NE2R40A	NE240B	4.0 ± 0.20	1.0x10^-2%	2.83 mm	NG9
NE550A	-	-	-	5.0 ± 0.25	1.0x10^-3%	3.55 mm	NG9
-	-	-	-	6.0 ± 0.30	1.0x10^-4%	1.5 mm	NG1

*The actual thickness of each ND filter is dependent on the optical density of the lot of glass used to manufacture each lot of ND filters.

Please Give Us Your Feedback

Email		Feedback On
(Optional)
Contact Me:
Your email address will NOT be displayed.

Please type the following key into the field to submit this form:

Click Here if you can not read the security code.
This code is to prevent automated spamming of our site
Thank you for your understanding.

Would this product be useful to you? Little Use 1 2 3 4Very Useful

Enter Comments Below:

Characters remaining 8000

Posted Comments:

Poster: klee

Posted Date: 2009-07-29 18:10:45.0

Response from Ken at Thorlabs to daniel.kraus: Unfortunately, the reflective ND filters are not recommended for pulsed laser use.

Poster: daniel.kraus

Posted Date: 2009-07-29 14:23:02.0

Dear Sir/Madam, are the reflective ND Filters suitable for pulsed laser applications? Kind Regards, Daniel Kraus

Poster: klee

Posted Date: 2009-07-29 12:06:37.0

Response from Ken at Thorlabs to daniel.kraus: Unfortunately, the reflective ND filters are not recommended for pulsed laser use.

Poster: Laurie

Posted Date: 2009-02-05 15:09:24.0

Response from Laurie at Thorlabs to r.a.loch: Thank you for your inquiry and interest in our products. The damage threshold for these absorptive ND filters is ~30W/cm^2 for a CW source. We do not recommend using these filters with pulsed light sources. If you have additional questions, please let us know.

Poster: r.a.loch

Posted Date: 2009-02-05 11:37:53.0

Dear Sir/Madam, What is the damage threshold for the Absorptive ND Filters? Kind regards, Rolf Loch

Click on any phrase below to search our site using our new Search Engine:

1 inch optic 1 optic 25 mm optic 25mm optic Filter iconel nd filter iconel nd filter kit metalic nd filter metalic nd filter kit ND neutral density filter neutral density filter kits neutral density filters reflective nd filter reflective nd filter kit

View All »Matching Part Numbers

Absorptive and Reflective Neutral Density Filter Kits

Features

Reflective ND Filters

UV Reflective ND Filters

Specifications

Kit Contents