microscopes, features, aspheric objectives, keyvisual

IWDO/LWDO

aspheric cryogenic objectives

The IWDO and LWDO aspheric objectives constitute an economic alternative to the LT-APO objectives, for appliations where either the apochromaticity is not essential, or an intermediate working distance is required. Besides, both objectives are available as fiber-based versions, which enables transmission measurements (attoCFM III, attoCFM IV) in a toploading cryostat with only an optical top window (attoDRY1000, attoDRY2100). Due the comparatively large focal displacement (chromatic focal shift), they are significantly less suitable for broadband optical measurements than their LT-APO counterparts. For more details, please consult the specification datasheets, or contact our sales engineers.

Objective LT-IWDO/0.68 LT-LWDO/0.55
compatible with. attoCFM I attoCFM II and III attoCFM I attoCFM II and III
numerical aperture (NA) 0.68 0.55
working distance 1.5 mm 2.7 mm
AR coating (> 80% trasnmission) 400 .. 1600 nm(2) 400 .. 1600 nm(2)
apochromatic range(3)
(δf < +/- Δ)
---
environments low temperatures(mK .. 300K), high magnetic fields, high vacuum
clear aperture 5.0 mm 4.95 mm
focal length 3.1 mm 4.51 mm
weight --- ---
diameter 12 mm 12 mm
length 32.9 mm 36.4 mm 31.8 mm 35.3 mm
suitable broadband collimator RT-APO/VIS-NIR/0.13
article number

1009849

1007211

1007212 1003961
download specs LT-IWDO/0.68 CFM I LT-IWDO/0.68 CFM II LT-LWDO/0.55 CFM I LT-LWDO/0.55 CFM II

 

(1) Possible use with solid immersion lenses: half-ball radius < 0.65 (0.70) mm for unlimited lateral displacement or half-ball radius < 1.40 mm for coaxial approach only
(2) 4 options available: coating A 400-600 nm | coating B 600-1050 nm | coating C 1050-1600 nm | uncoated

(3) δf: chromatic focal shift, Δ = n*λref / (2*NA2): depth of focus, n: refractive index, λref : wavelength used to define focal plane with max. Δ
(4) glas transmission: see respective objective data sheets
(5) RT-APO: > 96% transmission

Naming Scheme

The different objectives offered are distinguished and described by the following naming scheme:

RT is short for “Room Temperature (compatible)“.
LT is short for “Low Temperature (compatible)”.
IWDO is short for “Intermediate Working Distance Objective”.
LWD is short for “Long Working Distance”.
LWDO is short for “Long Working Distance Objective”.
APO is short for “Apochromatic”, and refers to the fact that the focal displacement curve is flat (i.e. within plus/minus one depth of focus) within the specified apochromatic range (see specification sheets of the respective objectives for further details).

/VIO indicates that the objective is most suitable in the ultra-violett to visible range
/VIS indicates that the objective is most suitable for the visible wavelength range.
/VISIR indicates that the objective is most suitable for the visible to (near-)infrared wavelength range.
/IR indicates that the objective is most suitable in the lower infrared range
/NIR indicates that the objective is most suitable for the near-infrared wavelength range.
/0.82 is indicating the numerical aperture (NA) of the respective objective, in this case NA = 0.82.