Microscope Immersion Oils

  • Designed for Use with Oil Immersion Objectives
  • Low Autofluorescence Oils Increase Image Contrast
  • Ideal for Fluorescence and Multiphoton Imaging

Fluorescence Image of Buttercup Root Taken with Immersion Oil Using a 40X, 1.3 NA Objective


Olympus Type F Immersion Oil


Cargille Type LDF Immersion Oil


Leica Type N Immersion Oil

Application Idea

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Refractive Indexa 1.518 at 546.1 nm
Abbe Numbera
(at 546.1 nm)
40.8 42.1 41 45.8
Type Olympus Type F Leica Type N Cargille Type LDF Leica Type F
Viscositya,b 450 mm2/s 825 mm2/s 500 mm2/s 435 mm2/s
Autofluorescence Low Low Very Low Very Low
Volume 30 mL / 28 g 20 mL 30 mL 10 mL
  • These values are specified at 23 °C.
  • 1 mm2/s = 1 cSt


  • Oils for Use with Oil Immersion Objectives
  • Very Low Autofluorescence Oils are Optimized for Fluorescence Microscopy
  • Non-Drying and Polychlorinated Biphenyl (PCB) Free

These Microscope Immersion Oils are designed for use with Oil Immersion Microscope Objectives. Placing an oil medium between the front surface of the objective and the cover glass allows the objective to achieve a high numerical aperture, maximizing light collection by the objective. To minimize refraction of light from the sample, the refractive index of each immersion oil is very close to those of cover glass.

Immersion oils are available with low or very low autofluorescence. Autofluorescence is the natural fluorescence emission of the oil when exposed to light. Each immersion oil has a different level of background emission, which either increases or decreases the contrast of the image; oils with very low autofluorescence are optimized for use in sensitive or UV fluorescence microscopy applications.

To clean immersion objectives after use with immersion oils, use a soft optical cleaning tissue such as our MC-5 premium lens tissues.

Posted Comments:
Bezia Lemma  (posted 2022-11-04 13:22:38.397)
Could you stock something equivalent to the Zeiss Immersol W, an oil with the refractive index of water? That would be nice.
cdolbashian  (posted 2022-11-08 02:09:29.0)
Thank you for the request! I have submitted this as an internal product request for a future release.
卓 王  (posted 2020-05-31 09:21:45.66)
Why can't I add it to the shopping cart and buy it?
YLohia  (posted 2020-06-02 01:15:59.0)
Hello, thank you for contacting Thorlabs. Our sales team will reach out to you directly.
user  (posted 2018-01-03 18:24:03.66)
Wondering how much Low/Very Low the Autofluorescence Oils is? Should be clear with definition of "LOW".
tfrisch  (posted 2018-01-04 03:57:28.0)
Hello, thank you for contacting Thorlabs. These autofluorescence levels are provided by the manufacturers without a technical definition. Any autofluorescence would depend on wavelength and incident power. Please contact TechSupport@Thorlabs.com if you need to discuss this further or request a sample.
garylin  (posted 2016-12-27 12:06:07.563)
Excuse me: I want to find the immersion oil for for microscopy, the specification is as follows. Refractive Index is 1.4 approx. Viscosity is less than 300 cSt. Thank you
tfrisch  (posted 2016-12-30 02:08:24.0)
Hello, thank you for contacting Thorlabs. I will reach out to you directly about availability of other immersion oils.
oleg.aseev  (posted 2015-06-11 17:02:21.143)
Hello we bought this oil and this is great. However, I cannot find the refractive index as a function of wavelength. This is important for our interferometry experiments. Would you please provide us with this imformation? Best regards, Oleg
besembeson  (posted 2015-09-21 10:14:48.0)
Response from Bweh at thorlabs USA: We don't have this data. I will check with Olympus and followup with you if they can provide more data other than what is written on the bottle.
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+1 Qty Docs Part Number - Universal Price Available
MOIL-30 Support Documentation
MOIL-30Low Autofluorescence Immersion Oil, n = 1.518, Olympus Type F, 30 mL
MOIL-20LN Support Documentation
MOIL-20LNLow Autofluorescence Immersion Oil, n = 1.518, Leica Type N, 20 mL
OILCL30 Support Documentation
OILCL30Very Low Autofluorescence Immersion Oil, n = 1.518, Cargille Type LDF, 30 mL
MOIL-10LF Support Documentation
MOIL-10LFVery Low Autofluorescence Immersion Oil, n = 1.518, Leica Type F, 10 mL