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Edge filters

from Andover

Often referred to as long wave pass (LWP) and short wave pass (SWP) filters, edge filters provide a well-defined transition between reflecting and transmitting regions. Essentially a modified quarter-wave stack, the filters use interference effects rather than absorption to isolate their spectral bands. Because edge filters will shift shorter with an increase in the angle of incidence, they are a good choice for fine-tuning the cut-on/cut-off wavelength. With their durable, first-surface dielectric coatings, Andover’s edge filters are built to withstand the normal cleaning and handling required by any high-quality optical component.

Features

Useful for redirecting a particular band of light
Provide steeper transition than color glass filters
Offer coverage over the 4001000 nm range

Specifications

General Specifications
Thickness	4.0 mm maximum
Size Tolerance	+0.0/-0.5 mm
Min. Clear Aperture	85% of outside dimension
Substrate Material	Glass (Note: BK-7 or Borofloat available as an Option for higher Tx)
Flatness	3-5 waves per 25 mm
Surface Quality	80/50 per MIL-C-48497A
Humidity and Abrasion	Per MIL-C-675A
Operating Temperature	-50 °C to +100 °C
Cut-on/cut-off Slopes	6% Maximum (10% for 300 nm filter)
Cut-on/cut-off Tolerance	±10 nm from 400-1000 nm ± 5 nm from 300-375 nm
Mechanical	Unmounted
Optional: Mounted in threaded ring - contact our expert on the right for thread sizes

Transmission
Long Wave Pass	85% average from the 50% cut-on point to 2000 nm
Short Wave Pass	85% average from the 50% cut-off point to 0.6 x the 50% cut-off point
Note: With the exception of the 400 nm filter, all SWP filters will drop off in transmission at wavelengths under 425 nm.

Rejection
Long Wave Pass	99% or greater from 0.9 x the 50% point to the ultraviolet
Short Wave Pass	99% or greater from 1.07 x the 50% point to 1.25 x the 50% point
Effective Index of Refraction (n*)	1.7 (approximately)

Visible
50% Point	Size, Shape & Part Number
50% Point	12.5 mm Ø	25 mm Ø	50 mm Ø	50 mm SQ
300 nm	300FH90-12.5	300FH90-25	300FH90-50	300FH90-50S
325 nm	325FH90-12.5	325FH90-25	325FH90-50	325FH90-50S
350 nm	350FH90-12.5	350FH90-25	350FH90-50	350FH90-50S
375 nm	375FH90-12.5	375FH90-25	375FH90-50	375FH90-50S
400 nm	400FH90-12.5	400FH90-25	400FH90-50	400FH90-50S
450 nm	450FH90-12.5	450FH90-25	450FH90-50	450FH90-50S
500 nm	500FH90-12.5	500FH90-25	500FH90-50	500FH90-50S
550 nm	550FH90-12.5	550FH90-25	550FH90-50	550FH90-50S
600 nm	600FH90-12.5	600FH90-25	600FH90-50	600FH90-50S
650 nm	650FH90-12.5	650FH90-25	650FH90-50	650FH90-50S
700 nm	700FH90-12.5	700FH90-25	700FH90-50	700FH90-50S

Near Infrared
50% Point	Size, Shape & Part Number
50% Point	12.5 mm Ø	25 mm Ø	50 mm Ø	50 mm SQ
750 nm	750FH90-12.5	750FH90-25	750FH90-50	750FH90-50S
800 nm	800FH90-12.5	800FH90-25	800FH90-50	800FH90-50S
850 nm	850FH90-12.5	850FH90-25	850FH90-50	850FH90-50S
900 nm	900FH90-12.5	900FH90-25	900FH90-50	900FH90-50S
950 nm	950FH90-12.5	950FH90-25	950FH90-50	950FH90-50S
1000 nm	100FH90-12.5	100FH90-25	100FH90-50	100FH90-50S

Visible
50% Point	Size, Shape & Part Number
50% Point	12.5 mm Ø	25 mm Ø	50 mm Ø	50 mm SQ
400 nm	400FL07-12.5	400FL07-25	400FL07-50	400FL07-50S
450 nm	450FL07-12.5	450FL07-25	450FL07-50	450FL07-50S
500 nm	500FL07-12.5	500FL07-25	500FL07-50	500FL07-50S
550 nm	550FL07-12.5	550FL07-25	550FL07-50	550FL07-50S
600 nm	600FL07-12.5	600FL07-25	600FL07-50	600FL07-50S
650 nm	650FL07-12.5	650FL07-25	650FL07-50	650FL07-50S
700 nm	700FL07-12.5	700FL07-25	700FL07-50	700FL07-50S

Near Infrared
50% Point	Size, Shape & Part Number
50% Point	12.5 mm Ø	25 mm Ø	50 mm Ø	50 mm SQ
750 nm	750FL07-12.5	750FL07-25	750FL07-50	750FL07-50S
800 nm	800FL07-12.5	800FL07-25	800FL07-50	800FL07-50S
850 nm	850FL07-12.5	850FL07-25	850FL07-50	850FL07-50S
900 nm	900FL07-12.5	900FL07-25	900FL07-50	900FL07-50S
950 nm	950FL07-12.5	950FL07-25	950FL07-50	950FL07-50S
1000 nm	100FL07-12.5	100FL07-25	100FL07-50	100FL07-50S