It comes down to the beam profile and how the energy propagates through the flow cytometer's optical system. How the manufacturer measures the profile seldom correlates to how the energy is distributed in the flow cell.
This is the most common mistake in qualifying a laser manufacturer. Using 2σ or 1/e2 clip levels are fine if the laser in question produces a nearly perfect Gaussian mode. However, lasers producing complex wavefront structures in the near-field, such as diode lasers, should NOT be measured this way.
There is a white paper published by one of the leading suppliers to the flow cytometry market. The information specific to the laser's mode quality in this document is very relevant to the behavior of the light inside a flow cell. This was an 18 month project managed by one of our engineers, and it is something we are experts on. You can also review the ISO11146-2 standard which provides the requirements for measuring the second order moments of the Wigner distribution. Understanding how to fully qualify and characterize your laser will allow you to better control your CVs!
This is the most common mistake in qualifying a laser manufacturer. Using 2σ or 1/e2 clip levels are fine if the laser in question produces a nearly perfect Gaussian mode. However, lasers producing complex wavefront structures in the near-field, such as diode lasers, should NOT be measured this way.
There is a white paper published by one of the leading suppliers to the flow cytometry market. The information specific to the laser's mode quality in this document is very relevant to the behavior of the light inside a flow cell. This was an 18 month project managed by one of our engineers, and it is something we are experts on. You can also review the ISO11146-2 standard which provides the requirements for measuring the second order moments of the Wigner distribution. Understanding how to fully qualify and characterize your laser will allow you to better control your CVs!
Consider this: If a laser light source has perfect optical power stability and pointing stability, in other words no change in power or position with respect to time, you would still have a signal dependency based on the cell’s position inside the stream relative to the laser’s intensity profile. Laser fluctuation in power and position as a function of time, becomes decreasingly important when considering higher throughput flow cytometers. Because hydrodynamic focusing creates larger positional fluctuation with higher throughput flow cytometers, the laser’s intensity profile becomes increasingly important.
This information is available from our engineers at no charge and under no obligation.
Please contact: flow.cytometry@claserapps.com
Our engineers have designed and integrated laser optical systems used in flow cytometer systems all over the world. Many of these systems have been functioning successfully for over a decade. One of the largest flow cytometer manufacturers developed their laser incoming QA process under the guidance of one or our engineers. We have provided technical support for some of the annual flow cytometer courses at Bowdoin College as well as being instrumental in changing the view of mode requirements for diode lasers used in flow cytometry. Our goal is to provide our partners with a competitive edge while expanding our own knowledge and experience in the process.
Here is a useful link: http://www.dutchflowgroup.nl - please note, there is some Dutch but most of the information is in English. Found a good flow cytometer troubleshooting site that might be helful: http://www.flowcytometrytroubleshooting.com
This information is available from our engineers at no charge and under no obligation.
Please contact: flow.cytometry@claserapps.com
Our engineers have designed and integrated laser optical systems used in flow cytometer systems all over the world. Many of these systems have been functioning successfully for over a decade. One of the largest flow cytometer manufacturers developed their laser incoming QA process under the guidance of one or our engineers. We have provided technical support for some of the annual flow cytometer courses at Bowdoin College as well as being instrumental in changing the view of mode requirements for diode lasers used in flow cytometry. Our goal is to provide our partners with a competitive edge while expanding our own knowledge and experience in the process.
Here is a useful link: http://www.dutchflowgroup.nl - please note, there is some Dutch but most of the information is in English. Found a good flow cytometer troubleshooting site that might be helful: http://www.flowcytometrytroubleshooting.com