attoCFM I+
PAGE 44
Cryogenic compatible, achromatic high-NA objectives
Maximum collection efficiency. Low focal displacement.
Many high spatial resolution spectroscopy measurements, such as
confocal micro-luminescence, fluorescence & micro-Raman require
cryogenic temperatures, where conventional room temperature objectives cannot be employed. Some simple aspheric lenses survive the
thermal cycling, but at the cost of an extremely poor chromatic performance: the focal plane typically shifts by almost 50 µm in a working
range of 500-1000 nm. This not only results in tedious operation, but is
also bound to produce irregular data when used over wider wavelength
ranges without precautions.
Now, attocube for the first time in cryogenic confocal microscopy is
able to offer three different apochromatic objectives for low temperatures. Besides high numerical apertures ranging from 0.81-0.82,
the biggest benefit is their small chromatic shift. Optimized for
465-600 nm, 565-770 nm and 700-985 nm respectively, the LT-APOs
keep the focal plane within one depth of focus (~ 1 µm), take care of a
uniform spot size, and the intensity of emitters stays within 75-100%.
Take a look at the overview below to see how your application can benefit from the new LT-APOs…
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
δf: chromatic focal shift, Δ = n*lref / (2*NA2): depth of focus, n: refractive index, lref: wavelength used to define focal plane with max. Δ
Suitable broadband collimators
available. Please contact attocube
for more information.