GRIN Lens Information - Revision history

DAharoni at 19:35, 29 November 2018

2018-11-29T19:35:30Z

Thebesteagle: /* GRIN Lens Issues */

2018-08-28T13:48:33Z

‎GRIN Lens Issues

DAharoni at 05:12, 9 May 2018

2018-05-09T05:12:42Z

Hishinuma: Undo revision 1678 by Hishinuma (talk)

2017-10-16T07:45:26Z

Undo revision 1678 by Hishinuma (talk)

Hishinuma at 07:41, 16 October 2017

2017-10-16T07:41:24Z

Hishinuma at 07:33, 16 October 2017

2017-10-16T07:33:28Z

Hishinuma: /* GRIN Lens Optics */

2017-10-16T07:02:55Z

‎GRIN Lens Optics

Cvickstrom: /* GRIN Lens Optics */ wrong word

2017-01-03T22:43:01Z

‎GRIN Lens Optics: wrong word

DAharoni: /* GRIN Lens Specifications for the Miniscope System */

2016-12-11T02:52:02Z

‎GRIN Lens Specifications for the Miniscope System

DAharoni: /* GRIN Lens Specifications for the Miniscope System */

2016-12-11T02:51:30Z

‎GRIN Lens Specifications for the Miniscope System

@@ Line 38: / Line 38: @@
 :Currently Grintech produces the best lenses for imaging applications but many people have experienced supply issues with them. The work presented on this site has all been done using Grintech lenses.
 ;Go!Foton (NSG)
-:Likely the largest manufacturer of GRIN lenses. Their product lines are mainly aimed at telecommunication applications and fiber coupling. They do sell an 'imaging' version of their lens and we are actively testing out these new lenses. We are also working with them to modify their production lines to produce high quality imaging GRIN lenses.
+:Likely the largest manufacturer of GRIN lenses. Their product lines are mainly aimed at telecommunication applications and fiber coupling. Over the past year or two GoFoton has developed GRIN lenses specifically for miniature microscopy applications. Contact Walter Boyles, <walter.boyles@gofoton.com>, at GoFoton for pricing and lens parts lists. NOTE: Lenses on the GoFoton website listed as "imaging" lenses will not perform as well as the newer lenses you can get directly from Walter so please contact him directly.
 ;Altechna/Chinese manufacturing
 :Altechna is a Lithuanian company with manufacturing in China. We have been in talks with them to improve the imaging properties of their lenses.

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 == GRIN Lens Issues ==
-As mentioned in the section above, the majority of commercially available GRIN lenses are manufactured with a second order sech profile causing poor off-axis focusing. While these lenses can resolve similar sized objects as forth order sech profile GRIN lenses they have much lower contrast. This is due to some angles of a point source of light not being focused to the same 3-dimensional spot as other angles of light from that same point source. This results in a nicely resolved image generated by some angles of light with a diffuse glow of light generated by other light angles. This proves to be a reasonably big issue when imaging neural activity since the unfocused, diffuse glow produced by most GRIN lenses increases your measured background fluorescence, making it difficult to pull out dF/F activity.
+As mentioned in the section above, the majority of commercially available GRIN lenses are manufactured with a second order sech profile causing poor off-axis focusing. While these lenses can resolve similar sized objects as fourth order sech profile GRIN lenses, they have much lower contrast. This is due to some angles of a point source of light not being focused to the same 3-dimensional spot as other angles of light from that same point source. This results in a nicely resolved image generated by some angles of light with a diffuse glow of light generated by other light angles. This proves to be a reasonably big issue when imaging neural activity since the unfocused, diffuse glow produced by most GRIN lenses increases your measured background fluorescence, making it difficult to pull out dF/F activity.
 Currently there seems to be only one manufacturer, Grintech, that produces GRIN lenses with a 4th order index of refraction profile. Additionally, Grintech uses an ion exchange process that has been certified to be bio-compatible. That being said, we have heard from many people that it can be difficult to get lenses from Grintech due to production limitations or exclusive sales agreements. For that reason we are actively working with other GRIN lens manufacturers to modify their product lines to produce high quality imaging GRIN lenses. More information on this topic can be found in the section below.

@@ Line 14: / Line 14: @@
 Our system currently uses a 0.25 pitch GRIN lens along with an achromatic lens to form an imaging on the microscope's imaging sensor. Sliding the imaging sensor up or down will shift the focal plane in the brain. We have successfully imaged hippocampus CA1, visual cortex, and subiculum using 2mm and 1.8mm diameter GRIN lenses. We are now in the process of testing smaller diameter relay lenses which will work in conjunction with the larger 0.25 pitch lens.
 == GRIN Lens Optics ==
-A nice overview of GRIN optics can be found on [[https://welcome.gofoton.com/product/imaging_lens]] and [[http://www.grintech.de/gradient-index-optics.html|Grintech.de]]. The most common use for GRIN lenses is for fiber coupling and light collimation and focusing. Aside from Grintech, all other GRIN lens manufacturers appear to produce GRIN lenses mainly for this use and not specifically for imaging. The index of refraction profile for most commercial GRIN lenses follow a second order expansion of a hyperbolic secant curve. The second order expansion (a parabola) is the ideal profile for on axis focusing of collimated light but has focusing issues of off axis light. Grintech uses an additional manufacturing step to add the fourth order expansion term of the hyperbolic secant to their index of refraction profile. The fourth order term improves off axis focusing which is very important for imaging applications. Theoretically there is not an ideal index of refraction profile for an imaging GRIN lens but the 4th order expansion term does a good enough job for imaging in our system.
+A nice overview of GRIN optics can be found on [[http://www.gofoton.com/product/selfoc-imaging-lenses/]] (click on "Physics of SELFOC") and [[http://www.grintech.de/gradient-index-optics.html|Grintech.de]]. The most common use for GRIN lenses is for fiber coupling and light collimation and focusing. Aside from Grintech, all other GRIN lens manufacturers appear to produce GRIN lenses mainly for this use and not specifically for imaging. The index of refraction profile for most commercial GRIN lenses follow a second order expansion of a hyperbolic secant curve. The second order expansion (a parabola) is the ideal profile for on axis focusing of collimated light but has focusing issues of off axis light. Grintech uses an additional manufacturing step to add the fourth order expansion term of the hyperbolic secant to their index of refraction profile. The fourth order term improves off axis focusing which is very important for imaging applications. Theoretically there is not an ideal index of refraction profile for an imaging GRIN lens but the 4th order expansion term does a good enough job for imaging in our system.
 Information about GRIN lens optics and manufacturing is a bit hard to find. We have listed a few papers below which provide nice insight on the topic

@@ Line 14: / Line 14: @@
 Our system currently uses a 0.25 pitch GRIN lens along with an achromatic lens to form an imaging on the microscope's imaging sensor. Sliding the imaging sensor up or down will shift the focal plane in the brain. We have successfully imaged hippocampus CA1, visual cortex, and subiculum using 2mm and 1.8mm diameter GRIN lenses. We are now in the process of testing smaller diameter relay lenses which will work in conjunction with the larger 0.25 pitch lens.
 == GRIN Lens Optics ==
-A nice overview of GRIN optics can be found on [[https://welcome.gofoton.com/product/imaging_lens|GoFoton]] and [[http://www.grintech.de/gradient-index-optics.html|Grintech.de]]. The most common use for GRIN lenses is for fiber coupling and light collimation and focusing. Aside from Grintech, all other GRIN lens manufacturers appear to produce GRIN lenses mainly for this use and not specifically for imaging. The index of refraction profile for most commercial GRIN lenses follow a second order expansion of a hyperbolic secant curve. The second order expansion (a parabola) is the ideal profile for on axis focusing of collimated light but has focusing issues of off axis light. Grintech uses an additional manufacturing step to add the fourth order expansion term of the hyperbolic secant to their index of refraction profile. The fourth order term improves off axis focusing which is very important for imaging applications. Theoretically there is not an ideal index of refraction profile for an imaging GRIN lens but the 4th order expansion term does a good enough job for imaging in our system.
+A nice overview of GRIN optics can be found on [[https://welcome.gofoton.com/product/imaging_lens]] and [[http://www.grintech.de/gradient-index-optics.html|Grintech.de]]. The most common use for GRIN lenses is for fiber coupling and light collimation and focusing. Aside from Grintech, all other GRIN lens manufacturers appear to produce GRIN lenses mainly for this use and not specifically for imaging. The index of refraction profile for most commercial GRIN lenses follow a second order expansion of a hyperbolic secant curve. The second order expansion (a parabola) is the ideal profile for on axis focusing of collimated light but has focusing issues of off axis light. Grintech uses an additional manufacturing step to add the fourth order expansion term of the hyperbolic secant to their index of refraction profile. The fourth order term improves off axis focusing which is very important for imaging applications. Theoretically there is not an ideal index of refraction profile for an imaging GRIN lens but the 4th order expansion term does a good enough job for imaging in our system.
 Information about GRIN lens optics and manufacturing is a bit hard to find. We have listed a few papers below which provide nice insight on the topic

@@ Line 14: / Line 14: @@
 Our system currently uses a 0.25 pitch GRIN lens along with an achromatic lens to form an imaging on the microscope's imaging sensor. Sliding the imaging sensor up or down will shift the focal plane in the brain. We have successfully imaged hippocampus CA1, visual cortex, and subiculum using 2mm and 1.8mm diameter GRIN lenses. We are now in the process of testing smaller diameter relay lenses which will work in conjunction with the larger 0.25 pitch lens.
 == GRIN Lens Optics ==
-A nice overview of GRIN optics can be found on [[https://welcome.gofoton.com/product/imaging_lens]] and [[http://www.grintech.de/gradient-index-optics.html|Grintech.de]]. The most common use for GRIN lenses is for fiber coupling and light collimation and focusing. Aside from Grintech, all other GRIN lens manufacturers appear to produce GRIN lenses mainly for this use and not specifically for imaging. The index of refraction profile for most commercial GRIN lenses follow a second order expansion of a hyperbolic secant curve. The second order expansion (a parabola) is the ideal profile for on axis focusing of collimated light but has focusing issues of off axis light. Grintech uses an additional manufacturing step to add the fourth order expansion term of the hyperbolic secant to their index of refraction profile. The fourth order term improves off axis focusing which is very important for imaging applications. Theoretically there is not an ideal index of refraction profile for an imaging GRIN lens but the 4th order expansion term does a good enough job for imaging in our system.
+A nice overview of GRIN optics can be found on [[https://welcome.gofoton.com/product/imaging_lens|GoFoton]] and [[http://www.grintech.de/gradient-index-optics.html|Grintech.de]]. The most common use for GRIN lenses is for fiber coupling and light collimation and focusing. Aside from Grintech, all other GRIN lens manufacturers appear to produce GRIN lenses mainly for this use and not specifically for imaging. The index of refraction profile for most commercial GRIN lenses follow a second order expansion of a hyperbolic secant curve. The second order expansion (a parabola) is the ideal profile for on axis focusing of collimated light but has focusing issues of off axis light. Grintech uses an additional manufacturing step to add the fourth order expansion term of the hyperbolic secant to their index of refraction profile. The fourth order term improves off axis focusing which is very important for imaging applications. Theoretically there is not an ideal index of refraction profile for an imaging GRIN lens but the 4th order expansion term does a good enough job for imaging in our system.
 Information about GRIN lens optics and manufacturing is a bit hard to find. We have listed a few papers below which provide nice insight on the topic

@@ Line 16: / Line 16: @@
 A nice overview of GRIN optics can be found on [[https://en.wikipedia.org/wiki/Gradient-index_optics|wikipedia]] and [[http://www.grintech.de/gradient-index-optics.html|Grintech.de]]. The most common use for GRIN lenses is for fiber coupling and light collimation and focusing. Aside from Grintech, all other GRIN lens manufacturers appear to produce GRIN lenses mainly for this use and not specifically for imaging. The index of refraction profile for most commercial GRIN lenses follow a second order expansion of a hyperbolic secant curve. The second order expansion (a parabola) is the ideal profile for on axis focusing of collimated light but has focusing issues of off axis light. Grintech uses an additional manufacturing step to add the fourth order expansion term of the hyperbolic secant to their index of refraction profile. The fourth order term improves off axis focusing which is very important for imaging applications. Theoretically there is not an ideal index of refraction profile for an imaging GRIN lens but the 4th order expansion term does a good enough job for imaging in our system.
-Information about GRIN lens optics and manufacturing is a bit hard to find. We have listed a few papers below which provide nice incite on the topic
+Information about GRIN lens optics and manufacturing is a bit hard to find. We have listed a few papers below which provide nice insight on the topic
 *Analysis of Refractive Index Distributions in Cylindrical, Graded- Index Glass Rods (GRIN Rods) Used as Image Relays
 **E. G. Rawson, D. R. Herriott, and J. McKenna

@@ Line 46: / Line 46: @@
 *We have successfully used 1.8mm and 2mm GRIN lenses from Grintech (which are about 4mm to 5mm in length) to image hippocampal CA1. Their respective part numbers are GT-IFRL-180_inf_50-NC and GT-IFRL-200_inf_50-NC.
 **If you are unsuccessful ordering these lenses from Grintech you can obtain 1.8mm diameter rebranded Grintech lenses from [http://www.edmundoptics.com/optics/optical-lenses/aspheric-lenses/gradient-index-grin-rod-lenses/3145/#f=categories_s|*C11I*,productId_i|3145,27614_s|1.8 Edmund Optics]. We have successfully tested part #64-519 but most 1.8mm diameter GRIN lenses sold by Edmund Optics should work.
-***You want to pick a lens between ~3.93mm and 4.31mm in length.
+***You want to pick a lens that has a length between ~3.93mm and 4.31mm.
 ***We have not tested any of the coated lenses.
 *GRIN lenses with a 4th order index of refraction profile will image significantly better than 2nd order lenses.

@@ Line 44: / Line 44: @@
 == GRIN Lens Specifications for the Miniscope System ==
 *Our system currently uses 2mm or 1.8mm diameter GRIN lenses with a pitch of (~0.25 + 0.5*N), where N is an integer.
 *We have successfully used 1.8mm and 2mm GRIN lenses from Grintech (which are about 4mm to 5mm in length) to image hippocampal CA1. Their respective part numbers are GT-IFRL-180_inf_50-NC and GT-IFRL-200_inf_50-NC.
- *If you are unsuccessful ordering these lenses from Grintech you can obtain 1.8mm diameter rebranded Grintech lenses from [http://www.edmundoptics.com/optics/optical-lenses/aspheric-lenses/gradient-index-grin-rod-lenses/3145/#f=categories_s|*C11I*,productId_i|3145,27614_s|1.8 Edmund Optics]. We have successfully tested part #64-519 but most 1.8mm diameter GRIN lenses sold by Edmund Optics should work. You want to pick a lens between ~3.93mm and 4.31mm in length. We have not tested any of the coated lenses.
+**If you are unsuccessful ordering these lenses from Grintech you can obtain 1.8mm diameter rebranded Grintech lenses from [http://www.edmundoptics.com/optics/optical-lenses/aspheric-lenses/gradient-index-grin-rod-lenses/3145/#f=categories_s|*C11I*,productId_i|3145,27614_s|1.8 Edmund Optics]. We have successfully tested part #64-519 but most 1.8mm diameter GRIN lenses sold by Edmund Optics should work.
 *GRIN lenses with a 4th order index of refraction profile will image significantly better than 2nd order lenses.
 *The overall length of your GRIN lens should stick far enough out of the skull to allow you to hold it during implantation and cement it to the skull.