try gold nano rods, as described here:
Application of ultrafast gold luminescence to measuring the instrument response function for multispectral multiphoton fluorescence lifetime imaging.
Optics Express: 2011 Jul 18;19(15):13848-61. doi: 10.1364/OE.19.013848.




Prof. Kurt I. Anderson
Tumor Cell Migration Lab and
Beatson Advanced Imaging Resource (BAIR)
The Beatson Institute for Cancer Research
Garscube Estate, Switchback Road, Glasgow  G61 1BD



• Direct Line +44 (0) 141 330 2864
• Fax                +44 (0) 141 942 6521
• E-mail

[log in to unmask]<https://mail.campus.gla.ac.uk/owa/redir.aspx?SURL=6BUWCm6RiBS6ZKio0WlxIllBRtFDaW3Hd6uHNmw7VVP73rNTf9jSCG0AYQBpAGwAdABvADoAawAuAGEAbgBkAGUAcgBzAG8AbgBAAGIAZQBhAHQAcwBvAG4ALgBnAGwAYQAuAGEAYwAuAHUAawA.&URL=mailto%3ak.anderson%40beatson.gla.ac.uk>



A company limited by guarantee; Registered in Scotland No 84170; A Registered Scottish Charity No SC006106



The information contained in this communication may be privileged and confidential and is intended for the exclusive use of the addressee designated above. If you are not the addressee, any disclosure, reproduction, distribution or other dissemination or use of this communication is strictly prohibited. If you have received this transmission in error please would you be kind enough to inform us.

On 19 Nov 2015, at 12:49, Hanna Sas Nowosielska <[log in to unmask]<mailto:[log in to unmask]>> wrote:

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
Post images on http://www.imgur.com and include the link in your posting.
*****

Dear Colleagues,



Could someone suggest me a fluorophore with lifetime short enough to
measure IRF in red channel (excitation: 520nm/ Detection : 565 – 605)? I
would be very grateful for an advice.



Best regards,

Hanna



--
Hanna Sas-Nowosielska

Laboratory of Imaging Tissue Structure and Function
Nencki Institute of Experimental Biology
Warsaw, Poland