microscopes, features, lwd objectives, keyvisual

LT-APO/LWD

apochromatic cryogenic objectives with long working distance

The LWD series of LT-APO objectives is designed for maximum numerical aperture and widest apochromatic range at an increased working distance of 5 mm. This strongly enhances compatibility with applications where more space is required between sample and objective, while still maintaining a relatively high NA combined with a broad working wavelength range. The different versions cover the range from the visible range (VIS, VISIR), up to the near-infrared (NIR). Their apochromatic range is mathematically defined by the range over which the focal shift is within +/- the depth of focus around an optimal focus wavelength.For best overall performance, the use of a broadband collimator is strongly recommended (see RT-APOs). Please note that the LWD series is not compatible with 1” sample spaces due to the larger overall size of the objective. For more details, please consult the specification datasheets, or contact our sales engineers.

Objective LT-APO/LWD/VIS/0.64 LT-APO/LWD/VISIR/0.65 LT-APO/LWD/NIR/0.63

compatible with.

CFM I/cust, AFM/CFM/cust, attoDRY800

numerical aperture (NA)

0.64 0.65 0.63

working distance

5.0 mm 5.0 mm 5.0 mm
AR coating
(> 80% trasnmission)
400 .. 1000 nm 400 .. 1000 nm 400 .. 1000 nm

apochromatic range(3)

(δf < +/- Δ)

480 .. 570 nm 570 .. 730 nm 725 .. 970 nm
environments cryogenic temperatures, high magnetic fields, high vacuum
(ultra-high vacuum on request)
clear aperture 4.7 mm 4.7 mm 4.7 mm
focal length 3.67 mm 3.62 mm 3.73 mm
weight ~100 g ~100 g ~100 g
diameter 28 mm 28 mm 28 mm
length 81 mm 81 mm 81 mm
suitable broadband collimator RT-APO/VIS-NIR/0.13 RT-APO/VIS-NIR/0.13 & RT-APO/NIR-IR
article number 1013373 1013374 1013375
download specs LT-APO/LWD/VIS/0.64 LT-APO/LWD/VISIR/0.65 LT-APO/LWD/NIR/0.63

 

(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.