How to respond to a company that wants specific details on implementation of my PhD research?
It's not normal to work for a company for free, and I'd simply answer something like this:


  Dear X,
  
  I am glad to know that my PhD work caught your interest. I can
  provide more information under a suitable consultancy contract.
  
  Kind regards, 
  
  L222


Note: We don't know the content of the company's email and, as some have remarked, the above response might be a bit too sharp, especially if their attitude is not so exploitative as I assumed. A milder approach, which I like, is that outlined in Dan Romik's answer. Since only you can read the email, I strongly encourage you to consider carefully both approaches, regardless of the accumulated votes.