For all intents and purposes, OD is the negative of the order of magnitude the factor by which the intensity of the light is reduced by the attenuating element with said OD.

What is optical density in microbiology

Optical density may also mean the absolute value of the logarithm with base 10 of the power transmission factor of an optical attenuator:

In other words: OD = 6, means that the intensity will be reduced by a factor of 10 to the power of -6, a.k.a by a factor of a million.

Optical density vs absorbance

2022912 — Figure 1.8.7: Polarization by reflection. Unpolarized light has equal amounts of vertical and horizontal polarization. After interaction with a ...

Optical density simpledefinition

Photodiodes are a type of detector, devices that generate an electrical signal when illuminated by light. ACP offers a variety of different types of ...

The first usage is as a synonym for refractive index, as described in the answers to the related question you cite. This is the commoner usage in physics.

Optical density spectrophotometer

Sep 19, 2022 — It then shoots a beam of light into the microscope, which becomes an image that you observe from the eyepiece containing the ocular lens.

Detail at the center of an image will virtually always have the highest MTF, and positions farther from the center will often have progressively lower MTF ...

For example, laser goggles marked $OD7\;488{\rm nm}$ means that the goggles will reduce incident power at 488nm by a factor of $10^7$. Goggles marked with a lone wavelength rather than a wavelength range are always meant for use with a particular kind of laser. For example, the $OD7\;488{\rm nm}$ goggles are meant for use with an argon ion laser. You cannot rely on them using another source of wavelength 485nm, for example.

QCL IR microscopy is a new and exciting field. We explain the basics of quantum cascade lasers and go into detail why infrared laser imaging is the next step ...

Optically dense definitionin chemistry

For example, an optical density of 3 means that the optical power is attenuated by the factor $10^3$ That would correspond to an attenuation by 30 decibels.

Optically dense definitionphysics

I'm a zoology minor and we are doing protein estimation by colorimetric method. I have stumbled upon a term 'Optical density'. I don't understand the term well. Is it a measure of the extent of light that can pass through a particular object?

Mar 29, 2016 — Online calculators using the formula FOV (rectilinear) = 2 * arctan (frame size/(focal length * 2) indicate that the 14mm focal length should ...

Optically dense definitionbiology

Full day and in-person bringing experts together to network with like-minded peers and learn about the latest optics and photonics technologies. Register for ...

Jul 5, 2019 — Their prices were breathtaking. They want $549 for a 4" achromat. That's $2058 in today's dollars. Today, you can get a 5" apochromatic doublet ...

Optical density formula

FYidoctor's collection spans an extensive array of Ray-Ban styles for everyone, each piece proudly bearing the emblematic logo of this iconic brand. Experience ...

The second usage is the total attenuation afforded by a protective screen, neutral density filter, laser goggles or the like. $ODx\; \lambda=y$ or even $ODx\; y$ means that the filter, goggles etc afford a power attenuation factor of $10^x$ at a light wavelength of $y$ or light wavelength range $y$. That is, the power transmitted through the filter is $10^{-x}$ of the incident power when the wavelength is as stated.

Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

To further the explanation above, I thought this image describing the second usage of optical density may be useful. The concept is being applied to a lens in regards to a laser passing through it. Each wavelength in the following chart will have its own OD but the notation is stating the minimum optical density over a range of wavelengths.

Once you've entered your monitor measurements and seating position, you'll see a list of FOV (Field of View) values for various sim racing games. These numbers ...

For generic use, a wavelength range must be specified. So, for example, one often sees $OD7\;450{\rm nm} - 510{\rm nm}$, meaning, pretty obviously, goggles that will give you seven orders of magnitude of attenuation over the whole range $450{\rm nm} \leq \lambda \leq 510{\rm nm}$.