Is there a way in AEM version 6.1 to get a list of all assets and associated meta data into an excel file?
AEM 6.4 :
There is not OOTB functionality in AEM 6.1 but it is available in AEM 6.4
If you are using acs-commons then you can use CSV Asset Importer, check below link
CSV Asset Importer
There are so many open source tools are available in the market to convert CSV to excel, so you can use those along with the ACS-Commons CSV Asset Importer.
I prefer this for single time execution or multiple times because it involves a manual approach
Custom solution ;
If you want to avoid converting CSV to Excel using a tool and you want to run this as cron job then it is better to write custom job
If the above step does not meet your requirement then you need to write custom code which reads all assets metadata and export it into excel format.
YOU can write a custom service and use Excel API - see this older community article for a discussion on use of Excel API - Adobe Experience Manager Help | Creating a Custom Reporting Service for Adobe Experience Manager