Glasgow, made up mainly of Scottish internationals, thrashed Leicester 43-0 away on Saturday to reach the last eight of Europe's premier club competition for the first time. And Edinburgh booked a quarter-final berth in the second-tier Challenge Cup.
"It was great getting the team back together on Sunday night. There was a buzz," Cotter said at the Six Nations launch in London.
"The silent indicators of the game in Scotland are shifting forward -- if you look at the pro teams and if you look at the depth coming through."
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Scotland host Ireland in their opening match on Feb. 4 and Cotter said the main target was to improve on the teams' two previous meetings in the tournament -- a 35-25 loss in Dublin last year and a 40-10 home defeat in 2015.
"If you talking about gains, we'd like to narrow that (difference) and show we are getting better," Cotter said.
He also said there was "a real dose of realism" in his squad after many of the players were involved in Glasgow's home defeat to Irish province Munster a few weeks ago.
LIONS TOUR
Of added incentive for Scotland's players is the chance to make their case for inclusion in the British and Irish Lions summer tour to New Zealand, with Cotter suggesting 10 Scots could be in contention.
Many pundits have already tipped fullback Stuart Hogg to become the first Scottish player to start a Lions test match since prop Tom Smith in 2001.
"From a players' point of view it is pretty exciting if they can put in some good performances and get a seat on that flight out to New Zealand," he said.
"I think it's great for the Scottish boys, there are players that come into contention and that is good for the game in Scotland."
Scotland won the last-ever Five Nations championship in 1999, before the inclusion of Italy, but their best finish since has been third.
"Are we real contenders for the Six Nations?," Cotter said. "I don't think that's the type of thing we are going to say in Scotland. We are a humble group of people who want to do well."
(Editing by Angus MacSwan)
